essay structure of an introduction

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How to Write an Essay Introduction (with Examples)   

The introduction of an essay plays a critical role in engaging the reader and providing contextual information about the topic. It sets the stage for the rest of the essay, establishes the tone and style, and motivates the reader to continue reading. 

Table of Contents

What is an essay introduction , what to include in an essay introduction, how to create an essay structure , step-by-step process for writing an essay introduction , how to write an introduction paragraph , how to write a hook for your essay , how to include background information , how to write a thesis statement .

• Argumentative Essay Introduction Example: 
• Expository Essay Introduction Example 

Literary Analysis Essay Introduction Example

Check and revise – checklist for essay introduction , key takeaways , frequently asked questions .

An introduction is the opening section of an essay, paper, or other written work. It introduces the topic and provides background information, context, and an overview of what the reader can expect from the rest of the work. 1 The key is to be concise and to the point, providing enough information to engage the reader without delving into excessive detail. 

The essay introduction is crucial as it sets the tone for the entire piece and provides the reader with a roadmap of what to expect. Here are key elements to include in your essay introduction: 

• Hook : Start with an attention-grabbing statement or question to engage the reader. This could be a surprising fact, a relevant quote, or a compelling anecdote. 
• Background information : Provide context and background information to help the reader understand the topic. This can include historical information, definitions of key terms, or an overview of the current state of affairs related to your topic. 
• Thesis statement : Clearly state your main argument or position on the topic. Your thesis should be concise and specific, providing a clear direction for your essay. 

Before we get into how to write an essay introduction, we need to know how it is structured. The structure of an essay is crucial for organizing your thoughts and presenting them clearly and logically. It is divided as follows: 2  

• Introduction:  The introduction should grab the reader’s attention with a hook, provide context, and include a thesis statement that presents the main argument or purpose of the essay.  
• Body:  The body should consist of focused paragraphs that support your thesis statement using evidence and analysis. Each paragraph should concentrate on a single central idea or argument and provide evidence, examples, or analysis to back it up.  
• Conclusion:  The conclusion should summarize the main points and restate the thesis differently. End with a final statement that leaves a lasting impression on the reader. Avoid new information or arguments. 

Here’s a step-by-step guide on how to write an essay introduction: 

• Start with a Hook : Begin your introduction paragraph with an attention-grabbing statement, question, quote, or anecdote related to your topic. The hook should pique the reader’s interest and encourage them to continue reading. 
• Provide Background Information : This helps the reader understand the relevance and importance of the topic. 
• State Your Thesis Statement : The last sentence is the main argument or point of your essay. It should be clear, concise, and directly address the topic of your essay. 
• Preview the Main Points : This gives the reader an idea of what to expect and how you will support your thesis. 
• Keep it Concise and Clear : Avoid going into too much detail or including information not directly relevant to your topic. 
• Revise : Revise your introduction after you’ve written the rest of your essay to ensure it aligns with your final argument. 

Here’s an example of an essay introduction paragraph about the importance of education: 

Education is often viewed as a fundamental human right and a key social and economic development driver. As Nelson Mandela once famously said, “Education is the most powerful weapon which you can use to change the world.” It is the key to unlocking a wide range of opportunities and benefits for individuals, societies, and nations. In today’s constantly evolving world, education has become even more critical. It has expanded beyond traditional classroom learning to include digital and remote learning, making education more accessible and convenient. This essay will delve into the importance of education in empowering individuals to achieve their dreams, improving societies by promoting social justice and equality, and driving economic growth by developing a skilled workforce and promoting innovation. 

This introduction paragraph example includes a hook (the quote by Nelson Mandela), provides some background information on education, and states the thesis statement (the importance of education). 

This is one of the key steps in how to write an essay introduction. Crafting a compelling hook is vital because it sets the tone for your entire essay and determines whether your readers will stay interested. A good hook draws the reader in and sets the stage for the rest of your essay.  

• Avoid Dry Fact : Instead of simply stating a bland fact, try to make it engaging and relevant to your topic. For example, if you’re writing about the benefits of exercise, you could start with a startling statistic like, “Did you know that regular exercise can increase your lifespan by up to seven years?” 
• Avoid Using a Dictionary Definition : While definitions can be informative, they’re not always the most captivating way to start an essay. Instead, try to use a quote, anecdote, or provocative question to pique the reader’s interest. For instance, if you’re writing about freedom, you could begin with a quote from a famous freedom fighter or philosopher. 
• Do Not Just State a Fact That the Reader Already Knows : This ties back to the first point—your hook should surprise or intrigue the reader. For Here’s an introduction paragraph example, if you’re writing about climate change, you could start with a thought-provoking statement like, “Despite overwhelming evidence, many people still refuse to believe in the reality of climate change.” 

Including background information in the introduction section of your essay is important to provide context and establish the relevance of your topic. When writing the background information, you can follow these steps: 

• Start with a General Statement:  Begin with a general statement about the topic and gradually narrow it down to your specific focus. For example, when discussing the impact of social media, you can begin by making a broad statement about social media and its widespread use in today’s society, as follows: “Social media has become an integral part of modern life, with billions of users worldwide.” 
• Define Key Terms : Define any key terms or concepts that may be unfamiliar to your readers but are essential for understanding your argument. 
• Provide Relevant Statistics:  Use statistics or facts to highlight the significance of the issue you’re discussing. For instance, “According to a report by Statista, the number of social media users is expected to reach 4.41 billion by 2025.” 
• Discuss the Evolution:  Mention previous research or studies that have been conducted on the topic, especially those that are relevant to your argument. Mention key milestones or developments that have shaped its current impact. You can also outline some of the major effects of social media. For example, you can briefly describe how social media has evolved, including positives such as increased connectivity and issues like cyberbullying and privacy concerns. 
• Transition to Your Thesis:  Use the background information to lead into your thesis statement, which should clearly state the main argument or purpose of your essay. For example, “Given its pervasive influence, it is crucial to examine the impact of social media on mental health.” 

A thesis statement is a concise summary of the main point or claim of an essay, research paper, or other type of academic writing. It appears near the end of the introduction. Here’s how to write a thesis statement: 

• Identify the topic:  Start by identifying the topic of your essay. For example, if your essay is about the importance of exercise for overall health, your topic is “exercise.” 
• State your position:  Next, state your position or claim about the topic. This is the main argument or point you want to make. For example, if you believe that regular exercise is crucial for maintaining good health, your position could be: “Regular exercise is essential for maintaining good health.” 
• Support your position:  Provide a brief overview of the reasons or evidence that support your position. These will be the main points of your essay. For example, if you’re writing an essay about the importance of exercise, you could mention the physical health benefits, mental health benefits, and the role of exercise in disease prevention. 
• Make it specific:  Ensure your thesis statement clearly states what you will discuss in your essay. For example, instead of saying, “Exercise is good for you,” you could say, “Regular exercise, including cardiovascular and strength training, can improve overall health and reduce the risk of chronic diseases.” 

Examples of essay introduction 

Here are examples of essay introductions for different types of essays: 

Argumentative Essay Introduction Example:  

Topic: Should the voting age be lowered to 16? 

“The question of whether the voting age should be lowered to 16 has sparked nationwide debate. While some argue that 16-year-olds lack the requisite maturity and knowledge to make informed decisions, others argue that doing so would imbue young people with agency and give them a voice in shaping their future.” 

Expository Essay Introduction Example  

Topic: The benefits of regular exercise 

“In today’s fast-paced world, the importance of regular exercise cannot be overstated. From improving physical health to boosting mental well-being, the benefits of exercise are numerous and far-reaching. This essay will examine the various advantages of regular exercise and provide tips on incorporating it into your daily routine.” 

Text: “To Kill a Mockingbird” by Harper Lee 

“Harper Lee’s novel, ‘To Kill a Mockingbird,’ is a timeless classic that explores themes of racism, injustice, and morality in the American South. Through the eyes of young Scout Finch, the reader is taken on a journey that challenges societal norms and forces characters to confront their prejudices. This essay will analyze the novel’s use of symbolism, character development, and narrative structure to uncover its deeper meaning and relevance to contemporary society.” 

• Engaging and Relevant First Sentence : The opening sentence captures the reader’s attention and relates directly to the topic. 
• Background Information : Enough background information is introduced to provide context for the thesis statement. 
• Definition of Important Terms : Key terms or concepts that might be unfamiliar to the audience or are central to the argument are defined. 
• Clear Thesis Statement : The thesis statement presents the main point or argument of the essay. 
• Relevance to Main Body : Everything in the introduction directly relates to and sets up the discussion in the main body of the essay. 

Writing a strong introduction is crucial for setting the tone and context of your essay. Here are the key takeaways for how to write essay introduction: 3  

• Hook the Reader : Start with an engaging hook to grab the reader’s attention. This could be a compelling question, a surprising fact, a relevant quote, or an anecdote. 
• Provide Background : Give a brief overview of the topic, setting the context and stage for the discussion. 
• Thesis Statement : State your thesis, which is the main argument or point of your essay. It should be concise, clear, and specific. 
• Preview the Structure : Outline the main points or arguments to help the reader understand the organization of your essay. 
• Keep it Concise : Avoid including unnecessary details or information not directly related to your thesis. 
• Revise and Edit : Revise your introduction to ensure clarity, coherence, and relevance. Check for grammar and spelling errors. 
• Seek Feedback : Get feedback from peers or instructors to improve your introduction further. 

The purpose of an essay introduction is to give an overview of the topic, context, and main ideas of the essay. It is meant to engage the reader, establish the tone for the rest of the essay, and introduce the thesis statement or central argument.  

An essay introduction typically ranges from 5-10% of the total word count. For example, in a 1,000-word essay, the introduction would be roughly 50-100 words. However, the length can vary depending on the complexity of the topic and the overall length of the essay.

An essay introduction is critical in engaging the reader and providing contextual information about the topic. To ensure its effectiveness, consider incorporating these key elements: a compelling hook, background information, a clear thesis statement, an outline of the essay’s scope, a smooth transition to the body, and optional signposting sentences.  

The process of writing an essay introduction is not necessarily straightforward, but there are several strategies that can be employed to achieve this end. When experiencing difficulty initiating the process, consider the following techniques: begin with an anecdote, a quotation, an image, a question, or a startling fact to pique the reader’s interest. It may also be helpful to consider the five W’s of journalism: who, what, when, where, why, and how.   For instance, an anecdotal opening could be structured as follows: “As I ascended the stage, momentarily blinded by the intense lights, I could sense the weight of a hundred eyes upon me, anticipating my next move. The topic of discussion was climate change, a subject I was passionate about, and it was my first public speaking event. Little did I know , that pivotal moment would not only alter my perspective but also chart my life’s course.” 

Crafting a compelling thesis statement for your introduction paragraph is crucial to grab your reader’s attention. To achieve this, avoid using overused phrases such as “In this paper, I will write about” or “I will focus on” as they lack originality. Instead, strive to engage your reader by substantiating your stance or proposition with a “so what” clause. While writing your thesis statement, aim to be precise, succinct, and clear in conveying your main argument.  

To create an effective essay introduction, ensure it is clear, engaging, relevant, and contains a concise thesis statement. It should transition smoothly into the essay and be long enough to cover necessary points but not become overwhelming. Seek feedback from peers or instructors to assess its effectiveness. 

References  

• Cui, L. (2022). Unit 6 Essay Introduction.  Building Academic Writing Skills . 
• West, H., Malcolm, G., Keywood, S., & Hill, J. (2019). Writing a successful essay.  Journal of Geography in Higher Education ,  43 (4), 609-617. 
• Beavers, M. E., Thoune, D. L., & McBeth, M. (2023). Bibliographic Essay: Reading, Researching, Teaching, and Writing with Hooks: A Queer Literacy Sponsorship. College English, 85(3), 230-242. 

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Awesome Guide on How to Write an Essay Introduction

'I'd like to recall the day I nearly burned myself in flames in my automobile while going 250 mph and escaping the police'. – Thankfully, we don't have a story like that to relate to, but we bet we piqued your interest.

That's what we refer to as an efficient hook. Fundamentally, it's an attention-grabbing first sentence that piques an audience's interest and encourages them to keep reading. While writing an essay, a strong hook in essay introductions is essential.

Delve into the article if you're wondering how to start an essay with a strong introduction. This is the ultimate guide for writing the parts of a introduction paragraph from our custom dissertation writing service to engage your readers.

Introduction Definition

The introduction paragraph, to put it simply, is the first section of an essay. Thus, when reading your essay, the reader will notice it right away. What is the goal of an opening paragraph? There are two things that an excellent introduction achieves. It initially informs the reader on the subject of your work; in other words, it should describe the essay's topic and provide some background information for its main point. It must also spark readers' interest and persuade them to read the remainder of your article.

To provide you with essay writing services , we only need your paper requirements to create a plagiarism-free paper on time.

How Long Should an Introduction Be

Typically, there are no strict restrictions on how long an opening paragraph should be. Professional essay writers often shape the size of it with the paper's total length in mind. For instance, if you wonder how to make introduction in essay with five paragraphs, keep your introductory sentence brief and fit it inside a single section. But, if you're writing a longer paper, let's say one that's 40 pages, your introduction could need many paragraphs or even be pages long.

Although there are no specific requirements, seasoned writers advise that your introduction paragraph should account for 8% to 9% of your essay's overall word length.

And, if you place an order on our coursework writing services , we will certainly comply with your introduction length requirements.

What Makes a Good Introduction

All of the following criteria should be fulfilled by a strong opening sentence:

• Start your introduction on an essay with a catchy sentence that draws the reader in.
• It needs to include baseline information about your subject.
• This should give readers a sense of the main argument(s) that your essay will address.
• It must include all necessary information on the setting, locations, and chronological events.
• By the end of your introduction, make a precise remark that serves as your essay's thesis.

What Are the 3 Parts of an Introduction Paragraph

So, what should be in a introduction paragraph? The introduction format essay has three sections: a hook, connections, and a thesis statement. Let's examine each component in more depth.

Part 1: Essay Hook

A hook is among the most effective parts of a introduction paragraph to start an essay. A strong hook will always engage the reader in only one sentence. In other words, it is a selling point.

Let's now address the query, 'how to make an essay introduction hook interesting?'. Well, to create a powerful hook, you can employ a variety of techniques:

• A shocking fact
• An anecdote 
• A short summary

And here is what to avoid when using a hook:

• Dictionary definitions
• Generalizations
• Sweeping statements that include words like 'everywhere,' 'always,' etc.

Once you've established a strong hook, you should give a general outline of your major point and some background information on the subject of your paper. If you're unsure how to write an introduction opening, the ideal approach is to describe your issue briefly before directing readers to particular areas. Simply put, you need to give some context before gradually getting more specific with your opinions.

The 5 Types of Hooks for Writing

Apart from the strategies mentioned above, there are even more types of hooks that can be used:

• A Common Misconception — a good trick, to begin with, to claim that something your readers believe in is false.

Example: 'Although many falsely believe that people working from home are less productive – employees who get such work-life benefits generally work harder.'

• Statistics — Statistical facts may provide a great hook for argumentative essays and serious subjects focusing on statistics.

Example: 'A recent study showed that people who are satisfied with their work-life balance work 21% harder and are 33% more likely to stay at the same company.'

• Personal Story — sometimes, personal stories can be an appropriate hook, but only if they fit into a few brief sentences (for example, in narrative essays).

Example: 'When I had my first work-from-home experience, I suddenly realized the importance of having a good work-life balance; I saw plenty of the benefits it can provide.'

• Scenes — this type of hook requires making the readers imagine the things you are writing about. It is most suitable when used in descriptive and narrative essays.

Example: 'Imagine you could have as much free time as you wish by working or studying from home—and spend more time with your loved ones.'

• Thesis Statement — when unsure how to do an essay introduction, some writers start directly with their thesis statement. The main trick here is that there is no trick.

Example: 'I strongly believe there is a direct correlation between a healthy work-life balance and productivity in school or at work.'

Part 2: Connections

Give readers a clearer sense of what you will discuss throughout your article once you have given a hook and relevant background information about your essay topic. Briefly mentioning your main points in the same sequence in which you will address them in your body paragraphs can help your readers progressively arrive at your thesis statement.

In this section of your introduction, you should primarily address the following questions:

You may make sure that you are giving your readers all the information they need to understand the subject of your essay by responding to each of these questions in two to three lines. Be careful to make these statements brief and to the point, though.

Your main goal is gradually moving from general to specific facts about your subject or thesis statement. Visualize your introduction as an upside-down triangle to simplify the essay writing process. The attention-grabbing element is at the top of this triangle, followed by a more detailed description of the subject and concluding with a highly precise claim. Here is some quick advice on how to use the 'upside-down triangle' structure to compose an essay introduction:

• Ensure that each subsequent line in your introduction is more focused and precise. This simple method will help you progressively introduce the main material of your piece to your audience.
• Consider that you are writing a paper on the value of maintaining a healthy work-life balance. In this situation, you may start with a query like, 'Have you ever considered how a healthy work-life balance can affect other areas of your life?' or a similar hook. Next, you could proceed by giving broad factual information. Finally, you could focus your topic on fitting your thesis statement.

Part 3: The Thesis Statement

If you're unsure of the ideal method to create an introduction, you should be particularly attentive to how you phrase your thesis statement.

The thesis of your work is, without a doubt, the most crucial section. Given that the thesis statement of your piece serves as the foundation for the entire essay, it must be presented in the introduction. A thesis statement provides readers with a brief summary of the article's key point. Your main assertion is what you'll be defending or disputing in the body of your essay. An effective thesis statement is often one sentence long, accurate, exact, unambiguous, and focused. Your thesis should often be provided at the end of your introduction.

Here is an example thesis statement for an essay about the value of a proper work-life balance to help you gain a better understanding of what a good thesis should be:

Thesis Statement Example: 'Creating flexible and pleasant work schedules for employees can help them have a better work-life balance while also increasing overall performance.'

Catchy Introductions for Different Essay Types

Although opening paragraphs typically have a fixed form, their language may vary. In terms of academic essays, students are often expected to produce four primary intro to essay examples. They include articles that are analytical, argumentative, personal, and narrative. It is assumed that different information should appear in these beginning paragraphs since the goals of each sort of essay change. A thorough overview of the various paper kinds is provided below, along with some good essay introduction samples from our argumentative essay writers:

Narrative Introduction

• The writer of a narrative essay must convey a story in this style of writing. Such essays communicate a story, which distinguishes them from other essay types in a big way.
• Such a paper's hook will often be an enticing glimpse into a specific scene that only loosely links to the thesis statement. Additionally, when writing such an essay, a writer should ensure that every claim included in the introduction relates to some important moments that have significantly impacted the story's outcome.
• The thesis in narrative writing is usually the theme or main lesson learned from the story.

Narrative introduction example: 'My phone rang, and my mother told me that Dad had suffered a heart attack. I suddenly experienced a sense of being lifted out from under me by this immaculately carpeted flooring. After making it through, Dad left me with a sizable collection of lessons. Here are three principles that I know dad would have wanted me to uphold...'

Still Can't Think of a Perfect Intro?

When assigned to write an essay, students end up with a ton of questions, including 'How to structure an essay?', 'How to choose a good topic?'. Here at EssayPro, we employ only the best essay writers who are committed to students’ success.

Analytical Introduction

• Analytical essay introduction format is another popular type. In contrast to a narrative paper, an analytical paper seeks to explore an idea and educate the reader about a topic.
• Three important facts that support the analytical premise should be included in the middle section of the introduction.
• A well-researched and well-thought-out claim will form a wonderful thesis because the main goal of this paper is to study the topic and educate readers. It's crucial to remember that this assertion shouldn't initially have any real weight. Although it will still be theoretical, it has to be articulated practically.

Analytical introduction example: “... Hence even though presidents, CEOs, and generals still have their daily schedules full of economic crises and military conflicts, on the cosmic scale of history humankind can lift its eyes up and start looking towards new horizons. If we bring famine, plague, and war under control, what will replace them at the top of the human agenda? Like firefighters in a world without fire, so humankind in the twenty-first century needs to ask itself an unprecedented question: what are we going to do with ourselves? What will demand our attention and ingenuity in a healthy, prosperous, and harmonious world? In a healthy, prosperous, and harmonious world, what will demand our attention and ingenuity? This question becomes doubly urgent given the immense new powers that biotechnology and information technology are providing us with. What will we do with all that power? ...” Homo Deus: A Brief History of Tomorrow, Yuval Noah Harari

Persuasive Introduction

• To persuade readers of anything is the sole goal of persuasive essay writing. This may be accomplished using persuasive strategies like ethos, pathos, and logos.
• A hook statement for this paper may be anything from a fascinating fact to even comedy. You can use whatever technique you choose. The most crucial advice is to ensure your hook is in line with your thesis and that it can bolster further justifications.
• Generally speaking, a persuasive essay must include three supporting facts. Hence, to gradually lead readers to the major topic of your paper, add a quick summary of your three arguments in your introduction.
• Last, the thesis statement should be the main claim you will be disputing in this paper. It should be a brief, carefully thought-out, and confident statement of your essay's major argument.

Persuasive introduction example: 'Recycling waste helps to protect the climate. Besides cleaning the environment, it uses waste materials to create valuable items. Recycling initiatives must be running all around the world. ...'

Personal Introduction

• The final sort of academic writing that students frequently encounter is a personal essay. In principle, this essay style is creative nonfiction and requires the author to reflect on personal experiences. The goals of such a paper may be to convey a story, discuss the lessons that certain incidents have taught you, etc. This type of writing is unique since it is the most personal.
• Whatever topic you choose can serve as the hook for such an essay. A pertinent remark, query, joke, or fact about the primary plot or anything else will be acceptable. The backdrop of your narrative should then be briefly explained after that. Lastly, a thesis statement can describe the impact of particular experiences on you and what you learned.

Personal introduction example: 'My parents always pushed me to excel in school and pursue new interests like playing the saxophone and other instruments. I felt obligated to lead my life in a way that met their standards. Success was always expected on the route they had set out for me. Yet eight years after my parents' separation, this course was diverted when my dad relocated to California...'

Tips for Writing a Winning Introduction Paragraph

You now understand how to do introduction and have specific intro example for essays to help you get going. Let's quickly examine what you should and shouldn't do during the writing process.

• Keep the assignment's purpose in mind when you write your introduction, and ensure it complies with your instructor's requirements.
• Use a compelling and relevant hook to grab the reader's attention immediately.
• Make sure your readers understand your perspective to make it apparent.
• If necessary, establish key terms related to your subject.
• Show off your expertise on the subject.
• Provide a symbolic road map to help readers understand what you discuss throughout the post.
• Be brief; it's recommended that your introduction make up no more than 8 to 9 percent of the entire text (for example, 200 words for a 2500 words essay).
• Construct a strong thesis statement.
• Create some intrigue.
• Make sure there is a clear and smooth transition from your introduction to the body of your piece.
• If you're looking for a custom writer , request assistance from the EssayPro team. We know how to write a term paper along with many other types of essays.

Don'ts

• Provide too much background information.
• Use sentences that are off-topic or unnecessary.
• Make your opening paragraph excessively long.
• Keep some information a secret and reveal it later in conclusion.
• Employ overused phrases or generalizations.
• Using quotation marks excessively

Now that you know what is in the introduction of an essay, we recommend reading the information on how to critique an article to gain more academic insight.

If you are still struggling with that, keep in mind that you can always send us your request to get professional assistance from our law essay writing service .

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How To Write An Essay Introduction?

What is the purpose of the introduction in an essay, how to start an essay introduction.

Daniel Parker

is a seasoned educational writer focusing on scholarship guidance, research papers, and various forms of academic essays including reflective and narrative essays. His expertise also extends to detailed case studies. A scholar with a background in English Literature and Education, Daniel’s work on EssayPro blog aims to support students in achieving academic excellence and securing scholarships. His hobbies include reading classic literature and participating in academic forums.

is an expert in nursing and healthcare, with a strong background in history, law, and literature. Holding advanced degrees in nursing and public health, his analytical approach and comprehensive knowledge help students navigate complex topics. On EssayPro blog, Adam provides insightful articles on everything from historical analysis to the intricacies of healthcare policies. In his downtime, he enjoys historical documentaries and volunteering at local clinics.

Related Articles

• If you are writing in a new discipline, you should always make sure to ask about conventions and expectations for introductions, just as you would for any other aspect of the essay. For example, while it may be acceptable to write a two-paragraph (or longer) introduction for your papers in some courses, instructors in other disciplines, such as those in some Government courses, may expect a shorter introduction that includes a preview of the argument that will follow.  
• In some disciplines (Government, Economics, and others), it’s common to offer an overview in the introduction of what points you will make in your essay. In other disciplines, you will not be expected to provide this overview in your introduction.  
• Avoid writing a very general opening sentence. While it may be true that “Since the dawn of time, people have been telling love stories,” it won’t help you explain what’s interesting about your topic.  
• Avoid writing a “funnel” introduction in which you begin with a very broad statement about a topic and move to a narrow statement about that topic. Broad generalizations about a topic will not add to your readers’ understanding of your specific essay topic.  
• Avoid beginning with a dictionary definition of a term or concept you will be writing about. If the concept is complicated or unfamiliar to your readers, you will need to define it in detail later in your essay. If it’s not complicated, you can assume your readers already know the definition.  
• Avoid offering too much detail in your introduction that a reader could better understand later in the paper.
• picture_as_pdf Introductions

How to write an Essay Introduction (5-Step Formula)

One of my friends – a high-up professor in an English university – told me he can tell the grade a student will get within the first 90 seconds of reading a paper.

This makes the introduction the most important paragraph in your whole paper.

The introduction orients your reader to how well you understand academic writing, your skills in critical thinking, your ability to write professionally with minimal errors, and the depth of knowledge you have on the topic.

All in one fantastic paragraph! No pressure.

No wonder introductions are so difficult to write. If you’re like me, you find that you can sit and stare at a blank page as the moments tick by. You’re just not sure how to write an introduction!

After reading the top 30 online articles on how to write an essay introduction, I synthesized the five most common steps that universities give on how to write an introduction.

The five steps I am going to introduce to you in this paragraph are from my I.N.T.R.O. method. The intro method provides an easy-to-use acronym for how to write an introduction that the top universities recommend.

The INTRO method’s steps are:

• [I] Interest: Provide an opening sentence that shows why the topic is of interest to everyday human beings
• [N] Notify: Notify the reader of background or contextual information
• [T] Translate: Translate the essay topic or question by paraphrasing it
• [R] Report: Report on your position or argument
• [O] Outline: Provide an outline of the essay structure

Below, I go through each step one by one. Each step is designed to be written in order, although you may feel free to mix them up after you’ve written each sentence to make it feel and read just the way you like.

Use the INTRO method as a guide for how to write an introduction and get words down on paper. As I often argue on this website, just writing something is often the hardest part .

You may also find that some essay introductions work better without one or more of these 5 steps. That is okay, too. Use these 5 steps as advice on points to include in an introduction and adjust them as you need. You may find in your specific area of study you need to add or remove other sentences. Play around with your introduction until you feel comfortable with it.

So don’t be too hard on yourself: have a go at a draft of your introduction with no pressure to use it in the end. You’ll find by the time you’ve written these five sentences you’ll have the creative juices flowing and a compelling introduction will be down on paper in no time.

1. Interest

Provide an opening sentence that shows why the topic is interesting to everyday human beings

Nearly every source on how to write an introduction that I found online recommended that your first sentence be an engaging ‘hook’ . Most sources highlight that the ‘hook’ sentence should draw in the reader’s interest in order to make your piece stand out.

The marker wants to see if you understand why this topic is of interest is in the first place. They want to see if you ‘get it’ from the very start.

I also recommend that you view the hook as an opportunity to show why the topic is interesting to everyday human beings . This makes it relevant to your reader.

To show you understand why the topic is of interest in the first place, aim to do one of the following things:

• Show what makes the topic worth discussing. Your ‘Interest’ sentence might help show why someone should care about the topic. Will it affect our livelihoods? Will it harm us? Make our work lives easier? The more relatable this point is to real human lives, the better.
• Highlight the single most interesting point in the essay. You might notice that you have already pointed out this interesting ‘hook’ somewhere in your essay. Find that interesting, relatable point and make it the opening sentence of your introduction.
• Use an interesting fact or figure to show the topic’s importance. Percentages or real numbers about how many people are or would be impacted by the issue help to show the topic’s importance. This will create reader interest with a ‘wow’ factor.
• Show how the essay topic is relevant to today’s world. If you’re struggling to identify this interesting ‘hook’, go onto google and find news reports related to your topic. How has the topic made it into the news recently? The news report will help you to brainstorm why this topic is of interest to the everyday lives of real human beings.

However, do not overstate the issue. You should provide a clear, reasonable perspective in this first sentence rather than an over-the-top claim. For example, aim to avoid hyperbolic or overly emotional phrases:

To find out more about retracting over-the-top emotion and hyperbole, we have put together a guide on academic language that you may like to read.

To summarize, I recommend that your first step in how to write an introduction is to write a ‘hook’ sentence that focuses on why the topic is interesting to everyday human beings . Use sober, clear facts about the importance of the topic to real human lives to get yourself started.

Read Also: My Suggested Best Words to Start a Paragraph

Notify the reader of background or contextual information

Nearly every source I found also recommended that you provide brief ‘background’ or ‘contextual’ information.

‘Background’ or ‘contextual’ information shows your depth of knowledge and understanding of the topic.

Here are some examples of ‘context’ for a few topics:

Hopefully, you can see here that giving ‘context’ is a way of showing that you have a really strong or deep knowledge of the history or background story of the topic. This is your chance to differentiate your depth of knowledge from other students. A sentence or two giving some of this context also helps to show off your knowledge right from the start.

Most sources recommend only providing one or two sentences of background information. This will help you to show off your knowledge without stealing content from the body of your essay. The body of the essay will add depth and detail to your points in the introduction, so feel free to leave out examples and explanations beyond your engaging sentence or two: you will have time in the body of the essay to elaborate.

3. Translate

Translate the essay topic or question

This point was mentioned by more than half the websites I found giving advice on how to write an introduction.

Many universities recommend re-stating the essay topic or question in your own words. This helps your marker to see that you understand the topic and are directly addressing it.

Here are some examples of essay questions and ways you can re-state the essay question in your introduction:

Something to keep in mind is that you do not want to appear to be re-stating the essay question simply to take up extra words. We call this ‘padding’. An example of padding is when a student drops the essay question in as a question, word-for-word:

• How can knowledge about history help us to improve our lives in the future? This is the question that will be answered in this essay.
• This essay will answer the question “What is the lasting impact of European Colonisation in the 21 st Century?”

Do not drop the essay question into the introduction without paraphrasing or surrounding explanation. If you do this, your marker will think you’re just trying to add words to the introduction because you’re not sure of anything interesting to say

Report your position or argument

Most essays do not require you to take a stance on an issue.

Essays that do require you to take a stance are called either ‘argumentative essays’ or ‘persuasive essays’.

If you are writing a persuasive essay, you will need to include Step 4: Report. For this step, you’ll need to state where you stand on the issue:

Keep in mind that essays should never leave a reader confused. Essay writing is not like creative writing: your reader must always know what’s going to be said right from the start. When reading to gather information, readers don’t like to be surprised. They want the facts up-front. Therefore, your marker will expect to know what your stance is on the issue right from the introduction onwards.

Provide an outline of the Essay Structure

This last point on how to write an introduction is important and separates average students from top students.

Introductions should always highlight the key points that will be made in an essay. Academic writing should never surprise the reader.

The fact that steps 4 and 5 both highlight that you should orient your marker reinforces the importance of this. Always, always, guide your marker’s reading experience.

Your essay should signpost all key concepts, theories, and main sections that make up your essay. If an important point is made in the essay but not signposted in the introduction, you are likely to confuse your marker. A confused marker very rapidly lowers your mark.

Too often, students fail to outline key points of their essays in the introduction. Make a habit of signposting your key ideas, points, theories, or concepts you will cover in the introduction in order to gain marks.

It is always easier to write this outline once the essay plan is written. You will then be able to gather together the key points that you listed in your essay plan and include them in the introduction.

The outline of the essay structure can only be one or two sentences long. You can state as your last sentence in your introduction:

• “Firstly, this essay … then, …, and finally …”
• “The essay opens with …, then, …, and then closes with …”
• “After exploring …, … and …, this essay will conclude with …”

Try to outline the issues you will cover in order. Providing an orderly outline of your essay is very helpful for your reader.

Now, I know that some people don’t like this method. Let me reassure you with this study from Theresa Thonney in 2016. Thonney examined 600 top-ranking articles in fields including Literature, Music, Environmental Sciences, Nutrition, Inter-Cultural Studies, and more to see how many articles used this method. In other words, she completed a comprehensive study of whether professional, published authors use this method of orientating the reader to the structure of the article.

Thonney found that 100% of top-ranking articles she looked at in the Astronomy field used this method. 98% of articles in Sociology journals used this method. In fact, the field with the lowest amount of authors who use this method is Art, which had 76% of authors use this method. In other words, even the lowest result she found showed that three in every four professional authors use this method.

So, you should too.

Let’s sum point 5 up by reinforcing this very important rule: your marker should always be very clear about what they will read, and in what order, to improve their reading experience.

A short list of things to Avoid in Introductions

I want to conclude this post with an outline of some of the worst things you can do in an introduction. The introduction sets the scene, so you want to make a good impression. You don’t want your marker taking away marks due to one of these top mistakes:

• Rhetorical Questions.
• Vague padding.
• Dictionary definitions.

Sometimes, teachers also recommend avoiding referencing in introductions. I have colleagues who absolutely refuse to let students include references in their introductions. Personally, I think that’s absurd – if a reference is required, include it! However, check with your teacher on their personal preferences here as I know this is a point of contention in faculty lounges.

The introduction is important for creating a strong first impression, especially since markers often make up their mind about your grade very early on in the marking process.

Introductions are best written last. That way, you will be able to include all the signposting you need to do (step 5), have a good understanding of the context (step 2), and be more certain about what your stance is on the issue (step 4).

Here’s the five INTRO steps I’d encourage you to use every time:

Once you have written your introduction, it is a good idea to put it away for a few days and then come back to edit it with fresh eyes . Remember that grammar and punctuation are important in the introduction. You want to leave a good impression.

If you have a friend who can read the draft for you and give you tips, or if your teacher has drop-in hours, use them to get some tips on how to write an introduction, what sounds right, want sounds off, and how you might be able to improve your introduction.

Once you have written your introduction, you might want to have a look at our guidance on how to write conclusions in order to end your piece as strongly as you started! People often think conclusions are just like introductions. That’s not true. Conclusions are unique paragraphs, so head over to our guidance on conclusions now to get the support you need on writing the best conclusion you can.

Chris Drew (PhD)

Dr. Chris Drew is the founder of the Helpful Professor. He holds a PhD in education and has published over 20 articles in scholarly journals. He is the former editor of the Journal of Learning Development in Higher Education. [Image Descriptor: Photo of Chris]

• Chris Drew (PhD) https://helpfulprofessor.com/author/chris-drew-phd/ 15 Self-Actualization Examples (Maslow's Hierarchy)
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It’s the roadmap to your essay, it’s the forecast for your argument, it’s...your introduction paragraph, and writing one can feel pretty intimidating. The introduction paragraph is a part of just about every kind of academic writing , from persuasive essays to research papers. But that doesn’t mean writing one is easy!

If trying to write an intro paragraph makes you feel like a Muggle trying to do magic, trust us: you aren’t alone. But there are some tips and tricks that can make the process easier—and that’s where we come in.

In this article, we’re going to explain how to write a captivating intro paragraph by covering the following info:  

• A discussion of what an introduction paragraph is and its purpose in an essay
• An overview of the most effective introduction paragraph format, with explanations of the three main parts of an intro paragraph
• An analysis of real intro paragraph examples, with a discussion of what works and what doesn’t
• A list of four top tips on how to write an introduction paragraph

Are you ready? Let’s begin!

What Is an Introduction Paragraph? 

An introduction paragraph is the first paragraph of an essay , paper, or other type of academic writing. Argumentative essays , book reports, research papers, and even personal  essays are common types of writing that require an introduction paragraph. Whether you’re writing a research paper for a science course or an argumentative essay for English class , you’re going to have to write an intro paragraph. 

So what’s the purpose of an intro paragraph? As a reader’s first impression of your essay, the intro paragraph should introduce the topic of your paper. 

Your introduction will also state any claims, questions, or issues that your paper will focus on. This is commonly known as your paper’s thesis . This condenses the overall point of your paper into one or two short sentences that your reader can come back and reference later.

But intro paragraphs need to do a bit more than just introduce your topic. An intro paragraph is also supposed to grab your reader’s attention. The intro paragraph is your chance to provide just enough info and intrigue to make your reader say, “Hey, this topic sounds interesting. I think I’ll keep reading this essay!” That can help your essay stand out from the crowd.

In most cases, an intro paragraph will be relatively short. A good intro will be clear, brief, purposeful, and focused. While there are some exceptions to this rule, it’s common for intro paragraphs to consist of three to five sentences . 

Effectively introducing your essay’s topic, purpose, and getting your reader invested in your essay sounds like a lot to ask from one little paragraph, huh? In the next section, we’ll demystify the intro paragraph format by breaking it down into its core parts . When you learn how to approach each part of an intro, writing one won’t seem so scary!

Once you figure out the three parts of an intro paragraph, writing one will be a piece of cake!

The 3 Main Parts of an Intro Paragraph

In general, an intro paragraph is going to have three main parts: a hook, context, and a thesis statement . Each of these pieces of the intro plays a key role in acquainting the reader with the topic and purpose of your essay. 

Below, we’ll explain how to start an introduction paragraph by writing an effective hook, providing context, and crafting a thesis statement. When you put these elements together, you’ll have an intro paragraph that does a great job of making a great first impression on your audience!

Intro Paragraph Part 1: The Hook

When it comes to how to start an introduction paragraph, o ne of the most common approaches is to start with something called a hook. 

What does hook mean here, though? Think of it this way: it’s like when you start a new Netflix series: you look up a few hours (and a few episodes) later and you say, “Whoa. I guess I must be hooked on this show!” 

That’s how the hook is supposed to work in an intro paragrap h: it should get your reader interested enough that they don’t want to press the proverbial “pause” button while they’re reading it . In other words, a hook is designed to grab your reader’s attention and keep them reading your essay! 

This means that the hook comes first in the intro paragraph format—it’ll be the opening sentence of your intro. 

It’s important to realize  that there are many different ways to write a good hook. But generally speaking, hooks must include these two things: what your topic is, and the angle you’re taking on that topic in your essay. 

One approach to writing a hook that works is starting with a general, but interesting, statement on your topic. In this type of hook, you’re trying to provide a broad introduction to your topic and your angle on the topic in an engaging way . 

For example, if you’re writing an essay about the role of the government in the American healthcare system, your hook might look something like this: 

There's a growing movement to require that the federal government provide affordable, effective healthcare for all Americans. 

This hook introduces the essay topic in a broad way (government and healthcare) by presenting a general statement on the topic. But the assumption presented in the hook can also be seen as controversial, which gets readers interested in learning more about what the writer—and the essay—has to say.

In other words, the statement above fulfills the goals of a good hook: it’s intriguing and provides a general introduction to the essay topic.

Intro Paragraph Part 2: Context

Once you’ve provided an attention-grabbing hook, you’ll want to give more context about your essay topic. Context refers to additional details that reveal the specific focus of your paper. So, whereas the hook provides a general introduction to your topic, context starts helping readers understand what exactly you’re going to be writing about

You can include anywhere from one to several sentences of context in your intro, depending on your teacher’s expectations, the length of your paper, and complexity of your topic. In these context-providing sentences, you want to begin narrowing the focus of your intro. You can do this by describing a specific issue or question about your topic that you’ll address in your essay. It also helps readers start to understand why the topic you’re writing about matters and why they should read about it. 

So, what counts as context for an intro paragraph? Context can be any important details or descriptions that provide background on existing perspectives, common cultural attitudes, or a specific situation or controversy relating to your essay topic. The context you include should acquaint your reader with the issues, questions, or events that motivated you to write an essay on your topic...and that your reader should know in order to understand your thesis. 

For instance, if you’re writing an essay analyzing the consequences of sexism in Hollywood, the context you include after your hook might make reference to the #metoo and #timesup movements that have generated public support for victims of sexual harassment. 

The key takeaway here is that context establishes why you’re addressing your topic and what makes it important. It also sets you up for success on the final piece of an intro paragraph: the thesis statement.

Elle Woods' statement offers a specific point of view on the topic of murder...which means it could serve as a pretty decent thesis statement!

Intro Paragraph Part 3: The Thesis

The final key part of how to write an intro paragraph is the thesis statement. The thesis statement is the backbone of your introduction: it conveys your argument or point of view on your topic in a clear, concise, and compelling way . The thesis is usually the last sentence of your intro paragraph. 

Whether it’s making a claim, outlining key points, or stating a hypothesis, your thesis statement will tell your reader exactly what idea(s) are going to be addressed in your essay. A good thesis statement will be clear, straightforward, and highlight the overall point you’re trying to make.

Some instructors also ask students to include an essay map as part of their thesis. An essay map is a section that outlines the major topics a paper will address. So for instance, say you’re writing a paper that argues for the importance of public transport in rural communities. Your thesis and essay map might look like this: 

Having public transport in rural communities helps people improve their economic situation by giving them reliable transportation to their job, reducing the amount of money they spend on gas, and providing new and unionized work .

The underlined section is the essay map because it touches on the three big things the writer will talk about later. It literally maps out the rest of the essay!

So let’s review: Your thesis takes the idea you’ve introduced in your hook and context and wraps it up. Think of it like a television episode: the hook sets the scene by presenting a general statement and/or interesting idea that sucks you in. The context advances the plot by describing the topic in more detail and helping readers understand why the topic is important. And finally, the thesis statement provides the climax by telling the reader what you have to say about the topic. 

The thesis statement is the most important part of the intro. Without it, your reader won’t know what the purpose of your essay is! And for a piece of writing to be effective, it needs to have a clear purpose. Your thesis statement conveys that purpose , so it’s important to put careful thought into writing a clear and compelling thesis statement. 

How To Write an Introduction Paragraph: Example and Analysis

Now that we’ve provided an intro paragraph outline and have explained the three key parts of an intro paragraph, let’s take a look at an intro paragraph in action.

To show you how an intro paragraph works, we’ve included a sample introduction paragraph below, followed by an analysis of its strengths and weaknesses.

Example of Introduction Paragraph

While college students in the U.S. are struggling with how to pay for college, there is another surprising demographic that’s affected by the pressure to pay for college: families and parents. In the face of tuition price tags that total more than $100,000 (as a low estimate), families must make difficult decisions about how to save for their children’s college education. Charting a feasible path to saving for college is further complicated by the FAFSA’s estimates for an “Expected Family Contribution”—an amount of money that is rarely feasible for most American families. Due to these challenging financial circumstances and cultural pressure to give one’s children the best possible chance of success in adulthood, many families are going into serious debt to pay for their children’s college education. The U.S. government should move toward bearing more of the financial burden of college education. 

Example of Introduction Paragraph: Analysis

Before we dive into analyzing the strengths and weaknesses of this example intro paragraph, let’s establish the essay topic. The sample intro indicates that t he essay topic will focus on one specific issue: who should cover the cost of college education in the U.S., and why. Both the hook and the context help us identify the topic, while the thesis in the last sentence tells us why this topic matters to the writer—they think the U.S. Government needs to help finance college education. This is also the writer’s argument, which they’ll cover in the body of their essay. 

Now that we’ve identified the essay topic presented in the sample intro, let’s dig into some analysis. To pin down its strengths and weaknesses, we’re going to use the following three questions to guide our example of introduction paragraph analysis: 

• Does this intro provide an attention-grabbing opening sentence that conveys the essay topic? 
• Does this intro provide relevant, engaging context about the essay topic? 
• Does this intro provide a thesis statement that establishes the writer’s point of view on the topic and what specific aspects of the issue the essay will address? 

Now, let’s use the questions above to analyze the strengths and weaknesses of this sample intro paragraph. 

Does the Intro Have a Good Hook? 

First, the intro starts out with an attention-grabbing hook . The writer starts by presenting  an assumption (that the U.S. federal government bears most of the financial burden of college education), which makes the topic relatable to a wide audience of readers. Also note that the hook relates to the general topic of the essay, which is the high cost of college education. 

The hook then takes a surprising turn by presenting a counterclaim : that American families, rather than students, feel the true burden of paying for college. Some readers will have a strong emotional reaction to this provocative counterclaim, which will make them want to keep reading! As such, this intro provides an effective opening sentence that conveys the essay topic. 

Does the Intro Give Context?

T he second, third, and fourth sentences of the intro provide contextual details that reveal the specific focus of the writer’s paper . Remember: the context helps readers start to zoom in on what the paper will focus on, and what aspect of the general topic (college costs) will be discussed later on. 

The context in this intro reveals the intent and direction of the paper by explaining why the issue of families financing college is important. In other words, the context helps readers understand why this issue matters , and what aspects of this issue will be addressed in the paper.  

To provide effective context, the writer refers to issues (the exorbitant cost of college and high levels of family debt) that have received a lot of recent scholarly and media attention. These sentences of context also elaborate on the interesting perspective included in the hook: that American families are most affected by college costs.

Does the Intro Have a Thesis? 

Finally, this intro provides a thesis statement that conveys the writer’s point of view on the issue of financing college education. This writer believes that the U.S. government should do more to pay for students’ college educations. 

However, the thesis statement doesn’t give us any details about why the writer has made this claim or why this will help American families . There isn’t an essay map that helps readers understand what points the writer will make in the essay.

To revise this thesis statement so that it establishes the specific aspects of the topic that the essay will address, the writer could add the following to the beginning of the thesis statement:

The U.S. government should take on more of the financial burden of college education because other countries have shown this can improve education rates while reducing levels of familial poverty.

Check out the new section in bold. Not only does it clarify that the writer is talking about the pressure put on families, it touches on the big topics the writer will address in the paper: improving education rates and reduction of poverty. So not only do we have a clearer argumentative statement in this thesis, we also have an essay map!  

So, let’s recap our analysis. This sample intro paragraph does an effective job of providing an engaging hook and relatable, interesting context, but the thesis statement needs some work ! As you write your own intro paragraphs, you might consider using the questions above to evaluate and revise your work. Doing this will help ensure you’ve covered all of your bases and written an intro that your readers will find interesting!

4 Tips for How To Write an Introduction Paragraph

Now that we’ve gone over an example of introduction paragraph analysis, let’s talk about how to write an introduction paragraph of your own. Keep reading for four tips for writing a successful intro paragraph for any essay. 

Tip 1: Analyze Your Essay Prompt

If you’re having trouble with how to start an introduction paragraph, analyze your essay prompt! Most teachers give you some kind of assignment sheet, formal instructions, or prompt to set the expectations for an essay they’ve assigned, right? Those instructions can help guide you as you write your intro paragraph!

Because they’ll be reading and responding to your essay, you want to make sure you meet your teacher’s expectations for an intro paragraph . For instance, if they’ve provided specific instructions about how long the intro should be or where the thesis statement should be located, be sure to follow them!

The type of paper you’re writing can give you clues as to how to approach your intro as well. If you’re writing a research paper, your professor might expect you to provide a research question or state a hypothesis in your intro. If you’re writing an argumentative essay, you’ll need to make sure your intro overviews the context surrounding your argument and your thesis statement includes a clear, defensible claim. 

Using the parameters set out by your instructor and assignment sheet can put some easy-to-follow boundaries in place for things like your intro’s length, structure, and content. Following these guidelines can free you up to focus on other aspects of your intro... like coming up with an exciting hook and conveying your point of view on your topic!

Tip 2: Narrow Your Topic

You can’t write an intro paragraph without first identifying your topic. To make your intro as effective as possible, you need to define the parameters of your topic clearly—and you need to be specific. 

For example, let’s say you want to write about college football. “NCAA football” is too broad of a topic for a paper. There is a lot to talk about in terms of college football! It would be tough to write an intro paragraph that’s focused, purposeful, and engaging on this topic. In fact, if you did try to address this whole topic, you’d probably end up writing a book!

Instead, you should narrow broad topics to  identify a specific question, claim, or issue pertaining to some aspect of NCAA football for your intro to be effective. So, for instance, you could frame your topic as, “How can college professors better support NCAA football players in academics?” This focused topic pertaining to NCAA football would give you a more manageable angle to discuss in your paper.

So before you think about writing your intro, ask yourself: Is my essay topic specific, focused, and logical? Does it convey an issue or question that I can explore over the course of several pages? Once you’ve established a good topic, you’ll have the foundation you need to write an effective intro paragraph . 

Once you've figured out your topic, it's time to hit the books!

Tip 3: Do Your Research

This tip is tightly intertwined with the one above, and it’s crucial to writing a good intro: do your research! And, guess what? This tip applies to all papers—even ones that aren’t technically research papers. 

Here’s why you need to do some research: getting the lay of the land on what others have said about your topic—whether that’s scholars and researchers or the mass media— will help you narrow your topic, write an engaging hook, and provide relatable context. 

You don't want to sit down to write your intro without a solid understanding of the different perspectives on your topic. Whether those are the perspectives of experts or the general public, these points of view will help you write your intro in a way that is intriguing and compelling for your audience of readers. 

Tip 4: Write Multiple Drafts

Some say to write your intro first; others say write it last. The truth is, there isn’t a right or wrong time to write your intro—but you do need to have enough time to write multiple drafts . 

Oftentimes, your professor will ask you to write multiple drafts of your paper, which gives you a built-in way to make sure you revise your intro. Another approach you could take is to write out a rough draft of your intro before you begin writing your essay, then revise it multiple times as you draft out your paper. 

Here’s why this approach can work: as you write your paper, you’ll probably come up with new insights on your topic that you didn’t have right from the start. You can use these “light bulb” moments to reevaluate your intro and make revisions that keep it in line with your developing essay draft. 

Once you’ve written your entire essay, consider going back and revising your intro again . You can ask yourself these questions as you evaluate your intro: 

• Is my hook still relevant to the way I’ve approached the topic in my essay?
• Do I provide enough appropriate context to introduce my essay? 
• Now that my essay is written, does my thesis statement still accurately reflect the point of view that I present in my essay?

Using these questions as a guide and putting your intro through multiple revisions will help ensure that you’ve written the best intro for the final draft of your essay. Also, revising your writing is always a good thing to do—and this applies to your intro, too!

What's Next?

Your college essays also need great intro paragraphs. Here’s a guide that focuses on how to write the perfect intro for your admissions essays. 

Of course, the intro is just one part of your college essay . This article will teach you how to write a college essay that makes admissions counselors sit up and take notice.

Are you trying to write an analytical essay? Our step-by-step guide can help you knock it out of the park.

Ashley Sufflé Robinson has a Ph.D. in 19th Century English Literature. As a content writer for PrepScholar, Ashley is passionate about giving college-bound students the in-depth information they need to get into the school of their dreams.

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Essay Introduction Examples

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Written by  Scribendi

Always have a road map for an essay introduction . Having a strong essay introduction structure is critical to a successful paper. It sets the tone for the reader and interests them in your work. It also tells them what the essay is about and why they should read it at all.

It shouldn't leave the reader confused with a cliffhanger at the end. Instead, it should generate interest and guide the reader to Chapter One. Using the right parts of an essay introduction can help with this.

Check out an effective essay introduction structure below. It’s a road map for writing an essay—just like the parts of essay introductions are road maps for readers.

Essay Introduction Structure

Attention-grabbing start

Outline of argument

Thesis statement

Some academics find the beginning the most difficult part of writing an essay , so our editors have created some examples of good essay introductions to guide you. Let's take a look at the samples below to see how the essay introduction structures come together. 

If you are unsure about your paper, our essay editors would love to give you some feedback on how to write an essay introduction. 

[1] According to Paul Ratsmith, the tenuous but nonetheless important relationship between pumpkins and rats is little understood: "While I've always been fascinated by this natural kinship, the connection between pumpkins and rats has been the subject of few, if any, other studies" (2008). [2] Ratsmith has been studying this connection, something he coined "pumpkinology," since the early 1990s. He is most well known for documenting the three years he spent living in the wild among pumpkins and rats. [3] Though it is a topic of little recent interest, the relationship has been noted in several ancient texts and seems to have been well understood by the Romans. Critics of Ratsmith have cited poor science and questionable methodology when dismissing his results, going so far as to call pumpkinology "rubbish" (de Vil, 2009), "stupid" (Claw, 2010), and "quite possibly made up" (Igthorn, 2009). [4] Despite these criticisms, there does appear to be a strong correlation between pumpkin patches and rat populations, with Ratsmith documenting numerous pumpkin–rat colonies across North America, leading to the conclusion that pumpkins and rats are indeed "nature's best friends" (2008).

Let's break down this example of a good essay introduction structure. The beginning hooks our attention from the get-go in section one. This is because it piques our curiosity. What is this strange relationship? Why has no one studied it? Then, section two gives us context for the topic. Ratsmith is an expert in a controversial field: pumpkinology. It's the study of the connection between pumpkins and rats. 

The second half of the paragraph also demonstrates why this is a good essay introduction example. Section three gives us the main argument: the topic is rarely studied because critics think Ratsmith's work is "rubbish," but the relationship between pumpkins and rats has ancient roots. Then section four gives us the thesis statement: Ratsmith's work has some merit.

The parts of an essay introduction help us chart a course through the topic. We know the paper will take us on a journey. It's all because the author practiced how to write an essay introduction. 

Let’s take a look at another example of a good essay introduction.

[1] Societies have long believed that if a black cat crosses one's path, one might have bad luck—but it wasn't until King Charles I's black cat died that the ruler's bad luck began (Pemberton, 2018). [2] Indeed, for centuries, black cats have been seen as the familiars of witches—as demonic associates of Satan who disrespect authority (Yuko, 2021). Yet, they have also been associated with good luck, from England's rulers to long-distance sailors (Cole, 2021). [3] This essay shows how outdated the bad luck superstition really is. It provides a comprehensive history of the belief and then provides proof that this superstition has no place in today's modern society. [4] It argues that despite the prevailing belief that animals cause bad luck, black cats often bring what seems to be "good luck" and deserve a new reputation.

This example of a good essay introduction pulls us in right away. This is because section one provides an interesting fact about King Charles I. What is the story there, and what bad luck did he experience after his cat passed away? Then, section two provides us with general information about the current status of black cats. We understand the context of the essay and why the topic is controversial.

Section three then gives us a road map that leads us through the main arguments. Finally, section four gives us the essay's thesis: "black cats often bring what seems to be 'good luck' and deserve a new reputation."

Still feeling unsure about how to write an essay introduction? Here's another example using the essay introduction structure we discussed earlier.

[1] When the Lutz family moved into a new house in Amityville, New York, they found themselves terrorized by a vengeful ghost (Labianca, 2021). Since then, their famous tale has been debunked by scientists and the family themselves (Smith, 2005). [2] Yet ghost stories have gripped human consciousness for centuries (History, 2009). Scientists, researchers, and theorists alike have argued whether ghosts are simply figments of the imagination or real things that go bump in the night. In considering this question, many scientists have stated that ghosts may actually exist. [3] Lindley (2017) believes the answer may be in the quantum world, which "just doesn’t work the way the world around us works," but "we don’t really have the concepts to deal with it." Scientific studies on the existence of ghosts date back hundreds of years (History, 2009), and technology has undergone a vast evolution since then (Lamey, 2018). State-of-the-art tools and concepts can now reveal more about ghosts than we've ever known (Kane, 2015). [4] This essay uses these tools to provide definitive proof of the existence of ghosts in the quantum realm. 

This example of a good essay introduction uses a slightly different strategy than the others. To hook the reader, it begins with an interesting anecdote related to the topic. That pulls us in, making us wonder what really happened to the Lutzs. Then, section two provides us with some background information about the topic to help us understand. Many people believe ghosts aren't real, but some scientists think they are.

This immediately flows into section three, which charts a course through the main arguments the essay will make. Finally, it ends with the essay's thesis: there is definitive proof of the existence of ghosts in the quantum realm. It all works because the author used the parts of an essay introduction well.

For attention-grabbing introductions, an understanding of essay introduction structure and how to write an essay introduction is required.

Our essay introduction examples showing the parts of an essay introduction will help you craft the beginning paragraph you need to start your writing journey on the right foot.

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Write an introduction that interests the reader and effectively outlines your arguments.

Every essay or assignment you write must begin with an introduction. It might be helpful to think of the introduction as an inverted pyramid. In such a pyramid, you begin by presenting a broad introduction to the topic and end by making a more focused point about that topic in your thesis statement. The introduction has three essential parts, each of which serves a particular purpose.

The first part is the "attention-grabber." You need to interest your reader in your topic so that they will want to continue reading. You also want to do that in a way that is fresh and original. For example, although it may be tempting to begin your essay with a dictionary definition, this technique is stale  because it has been widely overused. Instead, you might try one of the following techniques:

Offer a surprising statistic that conveys something about the problem to be addressed in the paper.

Perhaps you can find an interesting quote that nicely sums up your argument.

Use rhetorical questions that place your readers in a different situation in order to get them thinking about your topic in a new way.

If you have a personal connection to the topic, you might use an anecdote or story to get your readers emotionally involved.

For example, if you were writing a paper about drunk drivers, you might begin with a compelling story about someone whose life was forever altered by a drunk driver: "At eighteen, Michelle had a lifetime of promise in front of her. Attending college on a track scholarship, she was earning good grades and making lots of friends. Then one night her life was forever altered…"

From this attention grabbing opener, you would need to move to the next part of the introduction, in which you offer some relevant background on the specific purpose of the essay. This section helps the reader see why you are focusing on this topic and makes the transition to the main point of your paper. For this reason, this is sometimes called the "transitional" part of the introduction.

In the example above, the anecdote about Michelle might capture the reader's attention, but the essay is not really about Michelle. The attention grabber might get the reader thinking about how drunk driving can destroy people's lives, but it doesn't introduce the topic of the need for stricter drunk driving penalties (or whatever the real focus of the paper might be).

Therefore, you need to bridge the gap between your attention-grabber and your thesis with some transitional discussion. In this part of your introduction, you narrow your focus of the topic and explain why the attention-grabber is relevant to the specific area you will be discussing. You should introduce your specific topic and provide any necessary background information that the reader would need in order to understand the problem that you are presenting in the paper. You can also define any key terms the reader might not know.

Continuing with the example above, we might move from the narrative about Michelle to a short discussion of the scope of the problem of drunk drivers. We might say, for example: "Michelle's story is not isolated. Each year XX (number) of lives are lost due to drunk-driving accidents." You could follow this with a short discussion of how serious the problem is and why the reader should care about this problem. This effectively moves the reader from the story about Michelle to your real topic, which might be the need for stricter penalties for drinking and driving.

Finally, the introduction must conclude with a clear statement of the overall point you want to make in the paper. This is called your "thesis statement." It is the narrowest part of your inverted pyramid, and it states exactly what your essay will be arguing.

In this scenario, your thesis would be the point you are trying to make about drunk driving. You might be arguing for better enforcement of existing laws, enactment of stricter penalties, or funding for education about drinking and driving. Whatever the case, your thesis would clearly state the main point your paper is trying to make. Here's an example: "Drunk driving laws need to include stricter penalties for those convicted of drinking under the influence of alcohol." Your essay would then go on to support this thesis with the reasons why stricter penalties are needed.

In addition to your thesis, your introduction can often include a "road map" that explains how you will defend your thesis. This gives the reader a general sense of how you will organize the different points that follow throughout the essay. Sometimes the "map" is incorporated right into the thesis statement, and sometimes it is a separate sentence. Below is an example of a thesis with a "map."

"Because drunk driving can result in unnecessary and premature deaths, permanent injury for survivors, and billions of dollars spent on medical expenses,  drunk drivers should face stricter penalties for driving under the influence." The underlined words here are the "map" that show your reader the main points of support you will present in the essay. They also serve to set up the paper's arrangement because they tell the order in which you will present these topics.

In constructing an introduction, make sure the introduction clearly reflects the goal or purpose of the assignment and that the thesis presents not only the topic to be discussed but also states a clear position about that topic that you will support and develop throughout the paper. In shorter papers, the introduction is usually only one or two paragraphs, but it can be several paragraphs in a longer paper.

For Longer Papers

Although for short essays the introduction is usually just one paragraph, longer argument or research papers may require a more substantial introduction. The first paragraph might consist of just the attention grabber and some narrative about the problem. Then you might have one or more paragraphs that provide background on the main topics of the paper and present the overall argument, concluding with your thesis statement.

Below is a sample of an introduction that is less effective because it doesn't apply the principles discussed above.

An Ineffective Introduction

Everyone uses math during their entire lives. Some people use math on the job as adults, and others used math when they were kids. The topic I have chosen to write about for this paper is how I use math in my life both as a child and as an adult. I use math to balance my checkbook and to budget my monthly expenses as an adult. When I was a child, I used math to run a lemonade stand. I will be talking more about these things in my paper.

In the introduction above, the opening line does not serve to grab the reader's attention. Instead, it is a statement of an obvious and mundane fact. The second sentence is also not very specific. A more effective attention grabber may point out a specific, and perhaps surprising, instance when adults use math in their daily lives, in order to show the reader why this is such as important topic to consider.

Next the writer "announces" her topic by stating, "The topic I have chosen to write about…" Although it is necessary to introduce your specific topic, you want to avoid making generic announcements that reference your assignment. What you have chosen to write about will be evident as your reader moves through the writing. Instead, you might try to make the reader see why this is such an important topic to discuss.

Finally, this sample introduction is lacking a clear thesis statement. The writer concludes with a vague statement: "I will be talking more about these things in my paper."  This kind of statement may be referred to as a "purpose statement," in which the writer states the topics that will be discussed. However, it is not yet working as a thesis statement because it fails to make an argument or claim about those topics. A thesis statement for this essay would clearly tell the reader what "things" you will be discussing and what point you will make about them.

Now let's look at how the above principles can be incorporated more effectively into an introduction.

A More Effective Introduction

"A penny saved is a penny earned," the well-known quote by Ben Franklin, is an expression I have never quite understood, because to me it seems that any penny—whether saved or spent—is still earned no matter what is done with it. My earliest memories of earning and spending money are when I was ten years old when I would sell Dixie cups of too-sweet lemonade and bags of salty popcorn to the neighborhood kids. From that early age, I learned the importance of money management and the math skills involved. I learned that there were four quarters in a dollar, and if I bought a non-food item—like a handful of balloons—that I was going to need to come up with six cents for every dollar I spent. I also knew that Kool-Aid packets were 25 cents each or that I could save money and get five of them for a dollar. Today, however, money management involves knowing more than which combinations of 10-cent, five-cent, and one-penny candies I can get for a dollar. Proper money management today involves knowing interest rates, balancing checkbooks, paying taxes, estimating my paycheck, and budgeting to make ends meet from month-to-month.

In the first line the writer uses a well-known quotation to introduce her topic.

The writer follows this "attention-grabber" with specific examples of earning and spending money. Compare how the specific details of the second example paint a better picture for the reader about what the writer learned about money as a child, rather than this general statement: "As a child, I used math to run a lemonade stand." In the first introduction, this statement leaves the reader to guess how the writer used math, but in the second introduction we can actually see what the child did and what she learned.

Notice, too, how the reader makes the transition from the lessons of childhood to the real focus of her paper in this sentence: "Today, however, money management involves knowing…."

This transition sentence effectively connects the opening narrative to the main point of the essay, her thesis: "Proper money management today involves knowing  interest rates, balancing checkbooks, paying taxes, estimating my paycheck, and budgeting to make ends meet from month-to-month ." This thesis also maps out for the reader the main points (underlined here) that will be discussed in the essay.

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Academic Writing

• Introduction
• Planning an Essay
• Basic Essay Structure

Writing an Essay

• Writing Paragraghs
• Plagiarism This link opens in a new window

Basic academic essays have three main parts:

• introduction

• Video Explanation

Writing an Introduction

• Section  One  is a neutral sentence that will engage the reader’s interest in your essay.
• Section  Two  picks up the topic you are writing about by identifying the issues that you are going to explore.
• Section  Three  is an indication of how the question will be answered. Give a brief outline of how you will deal with each issue, and in which order.

An introduction   generally does three things. The first section is usually a  general comment  that shows the reader why the topic is important, gets their interest, and leads them into the topic. It isn’t actually part of your argument. The next section of the introduction is the  thesis statement . This is your response to the question; your final answer. It is probably the most important part of the introduction. Finally, the last section of an introduction tells the reader what they can expect in the essay body. This is where you  briefly outline your arguments .

Here is an example of the introduction to the question - Discuss how media can influence children. Use specific examples to support your view.

Writing Body Paragraphs

• The topic sentence  introduces  the topic of your paragraph.
• The sentences that follow the topic sentence will  develop and support the central idea  of your topic.
• The concluding sentence of your paragraph  restates the idea  expressed in the topic sentence.

The essay body itself is organized into paragraphs, according to your plan. Remember that each paragraph focuses on one idea, or aspect of your topic, and should contain at least 4-5 sentences so you can deal with that idea properly.

Each body paragraph has three sections. First is the  topic sentence . This lets the reader know what the paragraph is going to be about and  the main point it will make. It gives the paragraph’s point straight away. Next, come the  supporting sentences , which expand on the central idea, explaining it in more detail, exploring what it means, and of course giving the evidence and argument that back it up. This is where you use your research to support your argument. Then there is a  concluding sentence . This restates the idea in the topic sentence, to remind the reader of your main point. It also shows how that point helps answer the question.

Writing a Conclusion

• Re-read your introduction – this information will need to be restated in your conclusion emphasizing what you have proven and how you have proven it.
• Begin by  summarizing  your main arguments and restating your thesis ; e.g. "This essay has considered….."
• State your general conclusions,  explaining  why these are important.
• The final sentences should  draw together  the evidence you have presented in the body of the essay to restate your conclusion in an interesting way (use a transitional word to get you started e.g. Overall, Therefore).

The last section of an academic essay is the conclusion. The conclusion should reaffirm your answer to the question, and briefly summarize key arguments. It does not include any new points or new information.

A conclusion has three sections. First,  repeat the thesis statement . It won’t use the exact same words as in your introduction, but it will repeat the point: your overall answer to the question based on your arguments. Then set out your  general conclusions , and a short explanation of why they are important.  Finally,  draw together the question, the evidence in the essay body, and the conclusion. This way the reader knows that you have understood and answered the question. This part needs to be clear and concise.

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How To Structure Your MBA Essays

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A lot of people think they are not great storytellers. It’s true that some of us come by it more naturally than others. But with the proper structure and mindset, anybody can become a great storyteller. That’s why we’re diving deep into how to structure your MBA essays to tell your unique story. Remember, the AdCom member reading your materials only has about 15-20 minutes to form an impression of your candidacy. You don’t want them to merely like your application when they finish reading it.

“What you really want to be is the applicant they’re thinking about as they drive home that night, as they’re chatting with their spouse over spaghetti that evening,” explains SBC consultant and B-Schooled host Chandler Arnold. He recently sat down with fellow SBC consultant Kevin Rockmael to discuss essay writing strategy.

A few decades ago, business schools focused far more on applicants’ quantitative or technical skills when making admissions decisions. While your ability to handle the rigors of an MBA program is still a significant consideration, your emotional intelligence counts for an outsized amount these days. The so-called “soft skills” surrounding communication, the ability to motivate others, and leadership are attractive qualities to the admissions committee.

Chandler says that if you can demonstrate those soft skills in your essays, the AdCom is much more likely to take a chance on you. “Because they know that not only will you be successful… but more importantly, when you graduate, you’ll have a larger impact on companies. And that’s ultimately what these business schools are trying to accomplish.”

Your goal when drafting those essays is to make sure your stories are believable and authentic, SBC consultant Kevin explains. Does it seem real? Is your motivation clear? And perhaps most important, do you seem like someone the admissions committee is rooting for?

Curious about your chances of getting into a top B-school? Contact us to talk strategy with a free 15-minute MBA Advising Session with an SBC Principal Consultant.

HOW TO STRUCTURE YOUR MBA ESSAYS TO WIN OVER THE ADCOM

This is one of the topics SBC consultants get asked about the most. “I believe that structure is really the key part of the essay,” says Chandler. “So once you create that North Star, I think the second part is creating the structure, and then it’s actually filling in the sentences and then doing a lot of iteration to make sure that it all fits together.”

Some MBA applicants bristle at the idea, thinking that structure equals formulaic or that it will stunt their creativity. But we would urge you to flip that frame. Instead, think of structure as something that allows you to be more creative and compelling. When a reader senses there’s some structure to the material, it will enable them to relax and enjoy themselves as they read your essay.

The best essays are a balanced combination of a lot of different things. You’ll see personal stories. You’ll see specific accomplishments and experiences. You’ll get insights into what people have learned and how they’ve grown.

Here are the four main components SBC consultant Kevin advises you to consider as you structure your MBA essays.

Your Opening. What big problem have you seen or experienced that you want to solve?

Your Background. Talk about your background and the obstacles you have faced and learned from. 

Your Goal + Your Experience. What is missing from your background and experience? How will business school help you reach your long-term goals? Here is where you connect your dreams to the MBA program you’re interested in attending.

Conclusion . The last part of the essay is a wrap-up of the problem you discussed at the beginning and how you addressed it. Finally, explain how you will create a better world to solve that problem. 

B-Schooled co-host/Harvard MBA Erika Olson wants you to remember those three magic words of good storytelling: show, don’t tell. 

THE POWER OF THE CIRCLE

Another way to think about how to structure your MBA essays is to harken back to your favorite high school English teacher. Remember those standard five-paragraph essays? It may seem overly simplistic, but sometimes those simple things are the most powerful, Chandler notes.

• Paragraph 1: Start with an attention-grabbing first sentence or a personal anecdote. This surprises your reader and sets them up for the rest of your story.
• Paragraphs 2-4: Each could share one specific point supporting your argument. Maybe it’s a lesson you learn from college, your first job, etc. Use the STAR format to highlight your results and what you learned.
• Paragraph 5: Your conclusion harkens back to how you opened your essay. “I think there is a real power in kind of bringing things full circle,” Chandler says.

We often advise applicants to make a checklist of the key elements they want to cover in their entire application package.

• Are there personal stories?
• What about accomplishments?
• Have you done significant self-reflection?
• Did you highlight your leadership experience?
• Is there enough about grit and perseverance?

Find a trusted friend, colleague, or family member to read through your materials. Ask them to identify the major themes or takeaways they get from your entire package. You’ll learn a few things. Have you covered everything? Does it seem balanced? Or are you heavy in one particular direction? And if you are, then it’s time to fix it. You want to ensure that you’re building a package that tells your unique story. It should showcase you as a complete human and differentiate you from others within the application pool.

Get ready to put in the work.

Author Stephen King once said, “Talent is cheaper than table salt . What separates the talented individual from the successful one is a lot of hard work.” The hardest part is starting. And after that, everything gets easier. Best of luck on your MBA adventures; we can’t wait to read what you create.

Stacy Blackman Consulting’s Podcast, B-Schooled, is hosted by Erika Olson, Harvard MBA and Chandler Arnold, Stanford GSB MBA. B-Schooled now has more than a quarter million downloads and 200+ episodes.  Search and sort through our 200 B-Schooled podcasts . 

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The Structure and Influence of Han Dynasty Government

This essay is about the government structure of the Han Dynasty and its impact on Chinese civilization. It explains how the Han Dynasty maintained stability and promoted growth through a centralized bureaucracy, a merit-based civil service system, and the integration of Confucian and legalist principles. The essay highlights the roles of local administration, economic policies aimed at supporting agriculture and trade, and military strategies for defense and expansion. It also discusses the lasting legacy of the Han government on future Chinese dynasties and administrative practices. Overall, the essay underscores the sophistication and effectiveness of Han Dynasty governance.

How it works

The Han Epoch, spanning from 206 BCE to 220 CE, is often hailed as a zenith of Chinese civilization. Its governance exerted a pivotal influence on the cultural, societal, and political fabric of China. Grasping the configuration and operation of the Han Dynasty’s governance yields profound insights into its capacity to sustain stability, foster economic advancement, and nurture cultural flourishing across four centuries.

The Han Dynasty’s governance was typified by a highly centralized bureaucracy, marking a significant departure from the feudal structure of its antecedent, the Qin Dynasty.

Occupying the apex of this administrative hierarchy was the emperor, revered as the Son of Heaven and vested with supreme authority. However, effective administration necessitated a meticulously organized and efficient bureaucracy, an area where the Han government excelled.

A pivotal aspect of the Han administration was its civil service apparatus. Initially rooted in recommendations by local dignitaries, this system evolved into a structured examination regimen. Recognizing the imperative of appointing capable and loyal functionaries to administer the vast empire, Han rulers instituted civil service examinations assessing candidates’ familiarity with Confucian tenets. This emphasis on Confucianism as the state doctrine underscored the dynasty’s commitment to meritocracy, moral rectitude, and educational attainment, thus fostering the cultivation of a competent and principled administrative cadre.

The central authority was compartmentalized into various ministries, each tasked with distinct facets of governance, encompassing fiscal matters, military affairs, and judicial administration. These ministries were overseen by high-ranking officials directly accountable to the emperor. Foremost among them were the Chancellor (or Prime Minister), responsible for overarching administration, and the Imperial Secretary, tasked with managing imperial proclamations and communications. This division of labor streamlined governance, ensuring the efficient management of disparate state functions.

Local governance constituted another pivotal facet of the Han administration. The empire was demarcated into commanderies and counties, each under the stewardship of appointed officials. Charged with implementing central policies, levying taxes, upholding law and order, and supervising public infrastructure, these local administrators facilitated the extension of central authority to distant realms, fostering uniformity and cohesion across the empire.

The Han Dynasty accorded significant primacy to legalist precepts, particularly during its nascent phase. Legalism advocated for stringent legal codes and draconian penalties to enforce order and discipline. While Confucianism furnished the ethical bedrock of governance, legalist doctrines ensured uniform enforcement of laws and adherence to state decrees. Over time, the Han government synthesized these philosophical strands, fashioning a balanced paradigm that prized both ethical governance and legal exactitude.

Economic policy under the Han regime was oriented toward bolstering agricultural productivity and stabilizing the economy. Measures such as tax abatements, land redistribution, and state-run granaries were instituted to buttress agrarian interests and mitigate famine risks. These initiatives engendered an upsurge in agricultural yields, guaranteeing sustenance security for the populace. Furthermore, the Han Dynasty’s initiatives fostered extensive trade networks, both domestic and transnational, fostering economic expansion and cultural interchange.

Military organization and defense constituted paramount concerns for the Han government. Confronted with threats from nomadic confederations, notably the Xiongnu, the dynasty maintained a disciplined and well-organized military force. Investments were made in fortification construction, including the iconic Great Wall, to deter incursions and safeguard frontiers. Victorious military campaigns expanded the empire’s territorial dominion, augmenting its sway and influence.

The Han Dynasty’s governance ethos bequeathed an enduring legacy on Chinese political ruminations and administrative methodologies. The emphasis on meritocratic selection, centralized administration, and the fusion of Confucian and legalist ideals set a benchmark for subsequent Chinese dynasties. Particularly, the civil service mechanism emerged as a template for future epochs, influencing administrative paradigms in disparate cultural contexts.

To conclude, the governance of the Han Dynasty constituted a nuanced and sophisticated framework that harmonized central authority with local stewardship, ethical governance with legal rigor, and economic stewardship with military prudence. This efficacious governance paradigm empowered the Han Dynasty to uphold stability, foster economic prosperity, and nurture cultural efflorescence, imprinting an indelible mark on Chinese civilization. Delving into the intricacies of Han governance furnishes invaluable insights into the imperative of adept administration, ethical governance, and the amalgamation of divergent philosophical perspectives in statecraft.

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Media Companies Are Making a Huge Mistake With AI

News organizations rushing to absolve AI companies of theft are acting against their own interests.

In 2011, I sat in the Guggenheim Museum in New York and watched Rupert Murdoch announce the beginning of a “new digital renaissance” for news. The newspaper mogul was unveiling an iPad-inspired publication called The Daily . “The iPad demands that we completely reimagine our craft,” he said. The Daily shut down the following year, after burning through a reported $40 million.

For as long as I have reported on internet companies, I have watched news leaders try to bend their businesses to the will of Apple, Google, Meta, and more. Chasing tech’s distribution and cash, news firms strike deals to try to ride out the next digital wave. They make concessions to platforms that attempt to take all of the audience (and trust) that great journalism attracts, without ever having to do the complicated and expensive work of the journalism itself. And it never, ever works as planned.

Publishers like News Corp did it with Apple and the iPad, investing huge sums in flashy content that didn’t make them any money but helped Apple sell more hardware. They took payouts from Google to offer their journalism for free through search, only to find that it eroded their subscription businesses. They lined up to produce original video shows for Facebook and to reformat their articles to work well in its new app. Then the social-media company canceled the shows and the app. Many news organizations went out of business.

The Wall Street Journal recently laid off staffers who were part of a Google-funded program to get journalists to post to YouTube channels when the funding for the program dried up . And still, just as the news business is entering a death spiral, these publishers are making all the same mistakes, and more, with AI.

Adrienne LaFrance: The coming humanist renaissance

Publishers are deep in negotiations with tech firms such as OpenAI to sell their journalism as training for the companies’ models. It turns out that accurate, well-written news is one of the most valuable sources for these models, which have been hoovering up humans’ intellectual output without permission. These AI platforms need timely news and facts to get consumers to trust them. And now, facing the threat of lawsuits, they are pursuing business deals to absolve them of the theft. These deals amount to settling without litigation. The publishers willing to roll over this way aren’t just failing to defend their own intellectual property—they are also trading their own hard-earned credibility for a little cash from the companies that are simultaneously undervaluing them and building products quite clearly intended to replace them.

Late last year Axel Springer, the European publisher that owns Politico and Business Insider , sealed a deal with OpenAI reportedly worth tens of millions of dollars over several years. OpenAI has been offering other publishers $1 million to $5 million a year to license their content . News Corp’s new five-year deal with OpenAI is reportedly valued at as much as $250 million in cash and OpenAI credits. Conversations are heating up. As its negotiations with OpenAI failed, The New York Times sued the firm—as did Alden Global Capital, which owns the New York Daily News and the Chicago Tribune . They were brave moves, although I worry that they are likely to end in deals too.

That media companies would rush to do these deals after being so burned by their tech deals of the past is extraordinarily distressing. And these AI partnerships are far worse for publishers. Ten years ago, it was at least plausible to believe that tech companies would become serious about distributing news to consumers. They were building actual products such as Google News. Today’s AI chatbots are so early and make mistakes often. Just this week, Google’s AI suggested you should glue cheese to pizza crust to keep it from slipping off.

OpenAI and others say they are interested in building new models for distributing and crediting news, and many news executives I respect believe them. But it’s hard to see how any AI product built by a tech company would create meaningful new distribution and revenue for news. These companies are using AI to disrupt internet search—to help users find a single answer faster than browsing a few links. So why would anyone want to read a bunch of news articles when an AI could give them the answer, maybe with a tiny footnote crediting the publisher that no user will ever click on?

Companies act in their interest. But OpenAI isn’t even an ordinary business. It’s a nonprofit (with a for-profit arm) that wants to promote general artificial intelligence that benefits humanity—though it can’t quite decide what that means. Even if its executives were ardent believers in the importance of news, helping journalism wouldn’t be on their long-term priority list.

Ross Andersen: Does Sam Altman know what he’s creating?

That’s all before we talk about how to price the news. Ask six publishers how they should be paid by these tech companies, and they will spout off six different ideas. One common idea publishers describe is getting a slice of the tech companies’ revenue based on the percentage of the total training data their publications represent. That’s impossible to track, and there’s no way tech companies would agree to it. Even if they did agree to it, there would be no way to check their calculations—the data sets used for training are vast and inscrutable. And let’s remember that these AI companies are themselves struggling to find a consumer business model. How do you negotiate for a slice of something that doesn’t yet exist?

The news industry finds itself in this dangerous spot, yet again, in part because it lacks a long-term focus and strategic patience. Once-family-owned outlets, such as The Washington Post and the Los Angeles Times , have been sold to interested billionaires. Others, like The Wall Street Journal , are beholden to the public markets and face coming generational change among their owners. Television journalism is at the whims of the largest media conglomerates, which are now looking to slice, dice, and sell off their empires at peak market value. Many large media companies are run by executives who want to live to see another quarter, not set up their companies for the next 50 years. At the same time, the industry’s lobbying power is eroding. A recent congressional hearing on the topic of AI and news was overshadowed by OpenAI CEO Sam Altman’s meeting with House Speaker Mike Johnson . Tech companies clearly have far more clout than media companies.

Things are about to get worse. Legacy and upstart media alike are bleeding money and talent by the week. More outlets are likely to shut down, while others will end up in the hands of powerful individuals using them for their own agendas (see the former GOP presidential candidate Vivek Ramaswamy’s activist play for BuzzFeed ).

The long-term solutions are far from clear. But the answer to this moment is painfully obvious. Publishers should be patient and refrain from licensing away their content for relative pennies. They should protect the value of their work, and their archives. They should have the integrity to say no. It’s simply too early to get into bed with the companies that trained their models on professional content without permission and have no compelling case for how they will help build the news business.

Instead of keeping their business-development departments busy, newsrooms should focus on what they do best: making great journalism and serving it up to their readers. Technology companies aren’t in the business of news. And they shouldn’t be. Publishers have to stop looking to them to rescue the news business. We must start saving ourselves.

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• Published: 04 June 2024

The structure of the TH/INS locus and the parental allele expressed are not conserved between mammals

• Trent Newman   ORCID: orcid.org/0000-0002-6767-1429 1 ,
• Teruhito Ishihara   ORCID: orcid.org/0000-0002-2207-2473 1   nAff2 ,
• Geoff Shaw   ORCID: orcid.org/0000-0002-7421-7136 1 &
• Marilyn B. Renfree   ORCID: orcid.org/0000-0002-4589-0436 1  

Heredity ( 2024 ) Cite this article

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• Evolutionary genetics

Parent-of-origin-specific expression of imprinted genes is critical for successful mammalian growth and development. Insulin, coded by the INS gene, is an important growth factor expressed from the paternal allele in the yolk sac placenta of therian mammals. The tyrosine hydroxylase gene TH encodes an enzyme involved in dopamine synthesis. TH and INS are closely associated in most vertebrates, but the mouse orthologues, Th and Ins2 , are separated by repeated DNA. In mice, Th is expressed from the maternal allele, but the parental origin of expression is not known for any other mammal so it is unclear whether the maternal expression observed in the mouse represents an evolutionary divergence or an ancestral condition. We compared the length of the DNA segment between TH and INS across species and show that separation of these genes occurred in the rodent lineage with an accumulation of repeated DNA. We found that the region containing TH and INS in the tammar wallaby produces at least five distinct RNA transcripts: TH , TH-INS1 , TH-INS2 , lncINS and INS . Using allele-specific expression analysis, we show that the TH/INS locus is expressed from the paternal allele in pre- and postnatal tammar wallaby tissues. Determining the imprinting pattern of TH/INS in other mammals might clarify if paternal expression is the ancestral condition which has been flipped to maternal expression in rodents by the accumulation of repeat sequences.

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Marsupials have monoallelic MEST expression with a conserved antisense lncRNA but MEST is not imprinted

Balanced gene dosage control rather than parental origin underpins genomic imprinting

Evolution of imprinting via lineage-specific insertion of retroviral promoters

Introduction.

In one model of the evolution of genomic imprinting, increased maternal provision of resources to offspring in the mammalian lineage created a conflict between the parental genomes (Haig 2004 ; Smits et al. 2008 ). The placenta contributes to offspring development through several functions, including delivery of maternal nutrients and growth factors, and has been a focal point for investigating allelic gene expression under genomic conflict (Coan et al. 2005 ; Renfree et al. 2008 ; Bartolomei and Ferguson-Smith 2011 ; Tucci et al. 2019 ). Imprinting can also influence maternal investment through its function in postnatal tissues, such as the mammary gland and brain (Stringer et al. 2014 ; Cleaton et al. 2014 ; Tucci et al. 2019 ; Hanin and Ferguson-Smith 2020 ; John 2023 ). Relative to eutherians, the provision of resources to marsupial offspring is more pronounced during postnatal development but fewer imprinting studies have been made on these stages (Stringer et al. 2014 ; Hanin and Ferguson-Smith 2020 ). Parental conflict is entrenched in the literature as the primary selection pressure for genomic imprinting but other models could explain the evolution of imprinting for at least some genes (Spencer and Clark 2014 ).

Genomic imprinting has traditionally been studied in the fetus and the chorioallantoic placenta of mice and humans. The yolk sac evolved in fish while amniotes additionally developed the amnion, allantois and chorion. Mammals then adapted these four fetal membranes to support their in utero development (Mossman 1937 ; Ross and Boroviak 2020 ). Mammalian pregnancy depends on the yolk sac as the early site of maternal-fetal exchange, hematopoeiesis, and biosynthesis (Gulbis et al. 1998 ; Burton and Jauniaux 2021 ). In most marsupials it is the yolk sac that forms the definitive choriovitelline placenta and consists of an avascular bilaminar region (“BOM”: bilaminar omphalopleure) and a vascular trilaminar region (“TOM”: trilaminar omphalopleure), that in most species are closely apposed to the maternal uterine epithelium until birth (Renfree 1973 , 2010 ; Freyer et al. 2003 ; Guernsey et al. 2017 ). In humans and mice the yolk sac supports the early stages of development before the establishment of the definitive chorioallantoic placenta (Ross and Boroviak 2020 ; Burton and Jauniaux 2023 ).

Imprinted genes are special cases, comprising only a small proportion of all mammalian genes. More than 200 imprinted “genes” are known in humans, including distinct transcripts expressed from the same locus, with the majority paternally expressed (Morison et al. 2005 ; Tucci et al. 2019 ). Slightly more imprinted genes are known in mice, with a quarter of these genes imprinted in both human and mouse (Tucci et al. 2019 ). So far, 25 autosomal genes showing parent-of-origin-specific gene expression have been found in marsupials (Smits et al. 2008 ; Stringer et al. 2014 ; Douglas et al. 2014 ; Ishihara et al. 2022 ; Cao et al. 2023 ; Bond et al. 2023 ). In marsupials, and the early extraembryonic tissues of some eutherians, X-inactivation is non-random with the paternal X chromosome imprinted to undergo silencing (Sharman 1971 ; Cooper et al. 1971 ; Grant et al. 2012 ; Lee and Bartolomei 2013 ). Marsupial imprinted X-inactivation is known to involve paternal expression of an XIST -like (X-Inactive Specific Transcript) noncoding RNA, RSX (RNA-on-the-Silent X), and maternal expression of a TSIX (“ XIST ” backwards)-like RSX antisense transcript, XSR (“ RSX ” backwards) (Grant et al. 2012 ; Mahadevaiah et al. 2020 ).

Imprinting control regions (ICRs) regulate parent-of-origin-specific expression of a neighbouring cluster of genes (Jacob 2013 ; Juan and Bartolomei 2019 ; Chang and Bartolomei 2020 ). The most ancient ICR known is ICR1 which is paternally methylated in both eutherians and marsupials and associated with maternal expression of the noncoding RNA, H19 , and paternal expression of the insulin-like growth factor 2, IGF2 (Sparago et al. 2004 ; Smits et al. 2008 ). A nearby ICR, ICR2, is located within the potassium voltage-gated channel gene, KCNQ1 , and in eutherians has been associated with paternal expression of the KCNQ1 overlapping transcript ( KCNQ1OT1 ) and maternal expression of several other genes (Chiesa et al. 2012 ). ICR2 may not be present in marsupials because, although a KCNQ1OT1 transcript is present in the TOM placenta of the tammar wallaby, the gene lacks a proximal CpG island (Ager et al. 2008 ). The genes that neighbour ICR2 in humans, mice and other eutherians, CDKN1C (cyclin dependent kinase inhibitor 1 C) and PHLDA2 (pleckstrin homology-like domain family A member 2), are biallelically-expressed in the tammar wallaby (Suzuki et al. 2005 , 2011 ).

Aberrant imprinting in the human chromosome 11p15.5 region, containing ICR1 and ICR2, is associated with the Beckwith–Wiedemann (BWS) and Silver–Russell (SRS) syndromes. BWS and SRS are clinically opposite growth disorders, birth weights for BWS are >90th percentile while in SRS they are <3rd percentile (Wollman et al. 1995 ; Weksberg et al. 2010 ; Jacob et al. 2013 ; Eggermann et al. 2008 ). BWS/SRS have a range of molecular subtypes, ICR2 hypomethylation is the most frequent (50–60%) in BWS, with ICR1 hypermethylation (5–10%) also found; ICR1 hypomethylation is the most frequent (50–60%) for SRS (Eggermann et al. 2008 ; Wang et al. 2020 ). Loss of methylation at the maternal ICR2 allele in BWS reduces expression of the growth regulator CDKN1C while loss of methylation at the paternal ICR1 allele in SRS increases H19 which represses the growth promoting IGF2 (Nativio et al. 2011 ; Naveh et al. 2021 ). Expression of the genes in the 11p15.5 region is developmentally important but how parent-of-origin-specific gene expression is regulated at the interface of the two ICRs is unknown.

The tyrosine hydroxylase ( TH ) / insulin ( INS ) locus adjoining ICR1 and ICR2 has a dynamic evolutionary history of gene duplication and loss. The ancestral amino acid hydroxylase genes and insulin-like genes became linked in the genome of early chordates (Patton et al. 1998 ; Yamamoto et al. 2010 ). Duplication of the insulin-like gene early in the vertebrate lineage resulted in the neighbouring INS and IGF genes that encode structurally similar proteins (Chan and Steiner 2000 ). The duplication event that resulted in TH and phenylalanine hydroxylase ( PAH ) predates the divergence of invertebrates (Patton et al. 1998 ). A further duplication event in jawed vertebrates resulted in one paralogy group containing PAH, TH2 and IGF1 and another containing TH(1), INS and IGF2 , with the TH2 gene subsequently lost in therians but not birds (Patton et al. 1998 ; Candy and Collet 2005 ; Yamamoto et al. 2010 ).

The insulin gene, INS , is an important regulator of carbohydrate metabolism that is paternally-expressed in the therian yolk sac (Ager et al. 2007 ). In humans, INS is monoallelically-expressed from the paternal allele in the yolk sac at weeks 9 and 10 of gestation (Moore et al. 2001 ) and there is circumstantial evidence for monoallelic expression in the thymus (Pugliese et al. 1997 ), neonatal pancreas and an adolescent spleen (Pugliese and Miceli 2002 ). Murine rodents, mice and rats, have two insulin-coding genes, Ins1 and Ins2 , with Ins2 orthologous to the INS gene (Shiao et al. 2008 ). Ins1 and Ins2 are biallelically-expressed in mouse fetal pancreas and embryonic body, but only Ins2 is expressed in the yolk sac (Giddings et al. 1994 ; Deltour et al. 1995 , 2004 ). Both parental alleles of Ins2 are expressed in the yolk sac at embryonic day E12.5, but by E14.5 the maternal allele is silenced so that Ins2 is paternally-expressed in the yolk sac (Giddings et al. 1994 ; Deltour et al. 1995 , 2004 ). Deletion of the ICR1 and H19 region in mice results in activation of the Ins2 maternal allele in the E13.5 yolk sac, indicating that ICR1 can regulate imprinted expression of Ins2 in addition to Igf2 and H19 (Leighton et al. 1995 ).

The INS gene is paternally-expressed in the yolk sac and also in several postnatal tissues of the tammar wallaby (Stringer et al. 2012 ). INS has paternally-skewed expression in the BOM and TOM regions of the yolk sac placenta during the final third of the short, 26.5 day, tammar wallaby gestation after diapause (Ager et al. 2007 ). Marsupial mammals give birth to highly altricial young that are supported, usually in a pouch, by a sophisticated lactation process in which the composition of the milk changes dynamically throughout the whole of pouch life (Tyndale-Biscoe and Renfree 1987 ; Green et al. 1988 ; Trott et al. 2003 ; Stringer et al. 2014 ). Postnatally, INS is biallelically-expressed in the stomach and intestine, but monoallelically-expressed in the adult mammary gland and paternally-expressed in the tammar wallaby pouch young (PY) liver (Stringer et al. 2012 ).

The TH gene adjacent to INS encodes tyrosine hydroxylase: a key enzyme in the synthesis of catecholamines, particularly the neurotransmitter dopamine (Lelou et al. 2022 ). Th is maternally-expressed from E7.5 in the mouse placenta and embryo, but becomes biallelic within the embryo by E12.5 (Golding et al. 2011 ; Jones et al. 2011 ; Okae et al. 2012 ). In mice, the paternal Th allele is silenced in the E13.5 placenta but can be activated by deletion of ICR2 which prevents Kcnq1ot1 transcription (Jones et al. 2011 ), indicating that Th is imprinted by ICR2 in the mouse. Whether TH has parent-of-origin-specific expression is not known in humans (Lefebvre 2012 ; Cleaton et al. 2014 ), or any other species.

Synteny of TH and INS is well conserved in vertebrates, with the exception that INS was lost from the TH/IGF2 linkage group in some teleosts (Collet et al. 1998 ; Rotwein 2018 ). In chickens the distance between TH and INS is 15.5 kilobases (kb) while in humans the genes are 2.4 kb apart (Hernández-Sánchez et al. 2006 ). In contrast, the mouse orthologues, Th and Ins2 are separated by a 210 kb region of repetitive DNA rich in retro-elements (Shirohzu et al. 2004 ). Chimaeric TH-INS transcripts, which fuse exons from both TH and INS , have been observed in the developing chicken, quail (Hernández-Sánchez et al. 2006 ; De Pablo and de la Rosa 2011 ) and tammar wallaby (Stringer et al. 2012 , 2014 ). The chimaeric TH-INS proteins have lower enzymatic activity than TH but any roles for the chimaeric transcripts in regulating the expression of two adjacent genes, and any physiological implications, are unknown (Hernández-Sánchez et al. 2006 ).

Since insulin is a key hormone for growth and lactation in all mammals, we asked whether the large distance between Th and Ins2 in the mouse was an ancestral mammalian trait or specific to mice. We examined a range of vertebrate species and found that the large distance between these two genes in mice is a feature specific to rodents. Despite the position of the TH and INS genes at the interface of ICR1 and ICR2, it is unknown if TH is expressed from the maternal allele in any other species, as in mice. This study investigated the orthologous region in the tammar wallaby to identify transcribed RNAs and analyse parent-of-origin-specific expression in tammar wallaby fetuses and PY. We identified five transcripts, TH , TH-INS1 , TH-INS2 , lncINS and INS , produced from the tammar wallaby region and show that each has paternal expression.

Materials and methods

Species comparison.

The genomic location of TH and INS orthologues were taken from the 38 species listed in Supplementary Table 1 . The distance between TH and INS was calculated as the end position of the TH gene minus the starting position of the INS gene, these values are provided in Supplementary Table 1 . The species divergence times (mya) were taken from TimeTree 5 (Kumar et al. 2022 ), the divergence times relative to the house mouse are also noted in Supplementary Table 1 . The phylogeny was visualised using the Environment for Tree Exploration: ETE v3 (Huerta-Cepas et al. 2016 ). Repeat sequences in the region between the rodent Th and Ins(2) genes were assessed using RepeatMasker v4.1.5 (Tarailo-Graovac and Chen 2009 ) with the “-species rodent” option.

The location of genes in the imprinted region was visualised for house mouse, human, cattle and tammar wallaby using the DNA Features Viewer library (Zulkower and Rosser 2020 ). ICR locations were from NCBI (Gene ID: 105317033, 105259599) or based on the position of published bisulfite primers (Smits et al. 2008 ; Oh et al. 2008 ; Robbins et al. 2012 ; Wang et al. 2015 ; Huang et al. 2021 ). The position of KCNQ1OT1 in cattle and the tammar wallaby is from primer positions used to generate a short amplicon of the transcript (Ager et al. 2007 ; Robbins et al. 2012 ). Parent-of-origin-specific expression of genes in the region was from online databases https://www.geneimprint.com and https://corpapp.otago.ac.nz/gene-catalogue or literature, in the case of cattle KCNQ1OT1 (Robbins et al. 2012 ; Chen et al. 2015 ).

Animal samples

Tammar wallabies of Kangaroo Island, South Australia origin, were held in open grassy yards in our breeding colony at the University of Melbourne. A postnatal sample set was prepared containing tissues from 11 pouch young (PY) aged between 37 and 41 days postpartum (pp) and from 12 PY aged between day 78 and 81 pp, matched to maternal tissues. A prenatal sample set was prepared from the BOM and TOM placental tissues and the maternal endometrial tissues from 16 pregnant females and their fetuses collected between day 18 and 25 of the 26.5 day gestation. Tissue samples were collected as described previously (Suzuki et al. 2005 ; Ishihara et al. 2021 ) snap frozen in liquid nitrogen and stored at -80°C. After retrieval of the snap frozen PY whole brain tissue samples, the anterior portion of the brain including the olfactory bulb and the front half of the cerebrum was taken (Renfree et al. 1982 ) for RNA extraction. All tammar animal handling, husbandry and experimental sampling were in accordance with the National Health and Medical Research Council of Australia ( 2013 ) guidelines and approved by the University of Melbourne Animal Experimentation Ethics committees.

lncRNA identification

To identify potential antisense lncRNA at the TH/INS locus, a publicly available tammar testis RNA-seq data set was analysed (NCBI, DRX012262). Reads were trimmed using TrimGalore! v0.6.10 ( https://github.com/FelixKrueger/TrimGalore ), aligned to the tammar wallaby genome v7 using HISAT2 v2.2.1 (Kim 2019 ) with the “--rna-strandness FR” option and mapped reads assigned to each strand with Samtools v1.16.1 (Li et al. 2009 ).

To determine the full-length of the antisense INS lncRNA transcript, RACE (rapid amplification of cDNA ends) was performed with the SMARTer RACE 5′/3′ kit (cat. no. 634923, Clontech, California, USA). The first round RACE reactions were performed with adult testis cDNA using SeqAmp DNA Polymerase (cat no. 638504, Clontech, California, USA) with gene specific primers (Supplementary Table 2 ). Nested RACE experiments were performed with GoTaq Master Mix (cat. no. M5123, Promega, Madison, WI, USA) and products cloned using the pGEM-T Easy Vector System (cat. no. A1360, Promega, Madison, WI, USA) and JM109 Competent Cells (cat. no. L2001, Promega, Madison, WI, USA). Plasmids were extracted using the Wizard Plus SV Minipreps DNA Purification System (cat. no. A1460, Promega, Wisconsin, USA) and sent for Sanger sequencing by the Australian Genome Research Facility (AGRF).

Maternal and PY gDNA was prepared from frozen tissue using the Wizard Genomic DNA Purification Kit (cat. no. A1120, Promega, Madison, WI, USA) with a T10 basic handheld homogenizer (IKA, Staufen, Germany). Genotyping was carried out by PCR using the genotyping primers listed in Supplementary Table 2 . PCR products were extracted using the QIAquick Gel Extraction Kit (cat. no. 28706, Qiagen, Venlo, Netherlands) and sent for Sanger sequencing by AGRF. Informative animals were those in which the offspring was heterozygous at a site for which the corresponding maternal sample was homozygous.

PY RNA was prepared from frozen tissue using the GenElute Mammalian Total RNA Miniprep Kit (cat. no. RTN70-1KT, Sigma-Aldrich, St. Louis, MO, USA). cDNA was prepared from 1 μg of RNA using the Superscript IV First-Strand Synthesis System (cat. no. 18091050, ThermoFisher Scientific, Waltham, MA, USA), primed with oligo(dT) 20 . Allele-specific expression analysis of each SNP was performed in multiple animals with a single technical replicate of RT-PCR using the expression primers listed (Supplementary Tables 2 and 3 ). PCR products were gel extracted using the QIAquick Gel Extraction Kit (cat. no. 28706, Qiagen, Venlo, Netherlands) and sent for Sanger sequencing by AGRF.

Quantification of allele use

Parent-of-origin-specific gene expression was quantified by extracting the signal data from the .ab1 trace file. The signal intensity value for the major and minor alleles at an offspring SNP site was compared with reference to the identity of the genotyped maternal allele. The parental expression of the allele in the offspring cDNA was presented as a “mat:pat ratio”, the maternal signal / (maternal signal + paternal signal), metric which ranged from 0 to 1, where paternal expression was 0, biallelic expression was 0.5, and a value of 1 would indicate maternal expression. A mat:pat ratio of 0.00–0.20 or 0.80–1.00 was interpreted as “monoallelic”, 0.20–0.35 or 0.65–0.80 was interpreted as “skewed”, and 0.35–0.65 was interpreted as “biallelic”. The mean of multiple SNPs was taken and the final value provided is the mean ± standard error of the mean (SEM), across n animals.

Separation of the TH and INS genes in the rodent lineage

The DNA sequence between the orthologous TH and INS genes was assessed across 38 vertebrate species from diverse taxonomic groups (Fig. 1A ). Across non-rodent therian species the length of the DNA segment between TH and INS was 2.4 kb with a standard deviation of 1.3 kb. In the fish, amphibians and reptiles that were assessed the DNA segment was 20 ± 13 kb, or linkage of the two genes was not maintained as was the case in the teleost zebrafish which had th on chr25 and ins on chr5. In the rodent lineage the DNA between Th and Ins(2) was highly variable in length ranging from 3 kb in the naked mole-rat ( Heterocephalus glaber ) to 1357 kb in the red squirrel ( Sciurus vulgaris ). The house mouse ( Mus musculus ) was similar to other species of mice and had a large 213.1 kb DNA segment between the Th and Ins2 genes.

A The number of bases between the TH/Th and INS/Ins/Ins2 genes is given for different species and the relationships of those species are placed in terms of either their phylogenetic grouping or ( B ) the species divergence relative to the house mouse. Divergence times, millions of years ago (mya), are those indicated by TimeTree. Illustration of the gene locus ( A ) is not to scale. C The percent of the rodent DNA segment between Th and Ins(2) comprised of different classes of repeated elements is shown for the naked mole-rat, jerboa, rat and house mouse.

There was a progressive extension of the DNA segment between the Th and Ins2 genes in rodents (Fig. 1B ). The Hystricognathi clade, including the naked mole-rat and degu ( Octodon degus ), shared an ancestor with the murine rodents (Muroidea), including the house mouse, 70 mya and, with the exception of the chinchilla ( Chinchilla lanigera ), had a short DNA segment that was comparable to non-rodent therians. The jerboa ( Jaculus jaculus ) and the prairie vole ( Microtus ochrogaster ) diverged from mice 53 and 27 mya and had DNA segments that were 38 and 71 kb long respectively. The rat ( Rattus norvegicus ) shared an ancestor with the house mouse 13 mya and had 79 kb of DNA between Th and Ins2 , reflecting a recent rapid extension in the length of the DNA segment in mice. The squirrel-related clade, including the red squirrel and striped gopher ( Ictidomys tridecemlineatus ), was an exception to this progression diverging from mice 69 mya yet having a DNA segment longer than 785 kb, suggesting a distinct evolutionary process in the squirrel lineage.

To gain insight into the DNA separating Th and Ins(2) in rodents we profiled the repeated element composition (Fig. 1A, C ). Across the rodent species assessed, repeated elements comprised 35 ± 15% of the DNA segment. The amount of repeated DNA progressively increased between the Th and Ins(2) genes in the mouse-related clade. The jerboa which diverged before Muroidea had a distinct accumulation of long interspersed nuclear elements (LINEs) that made up 52% of the DNA between Th and Ins in this species. In Muroidea long terminal repeats (LTRs) were the largest subclass of repeated elements found. In the house mouse LTRs made up 30%, or 63.9 kb, of the DNA between the Th and Ins2 genes. The most common individual LTR was MYSERV-int : a murine-specific endogenous retroelement which alone made up 6%, or 7 kb, of the house mouse DNA segment, the MYSERV6-int element contributed an additional 6.1 kb. LTRs were also prominent in the squirrel-related clade, making up 450.7 kb of the DNA segment in the red squirrel.

To put the mouse Th / Ins2 locus in the context of imprinting regulation, the gene positions were visualised to scale in the broader region (Fig. 2 ). In the house mouse the start site of the paternally-expressed Ins2 gene was closer to ICR1 while the start site of the maternally-expressed Th gene was positioned halfway (48.9% of the distance) between ICR1 and ICR2 (Fig. 2A ). In humans and cattle, species for which ICR positions are known, the start site of TH gene was positioned closer to ICR1, less than a quarter of the way between ICR1 and ICR2 (Fig. 2B, C ). Parent-of-origin-specific expression for genes within the ICR1/ICR2 region has been best characterised in the house mouse with the imprinting status of TH , and multiple other genes, unknown in other species. Here we find, below, that TH is paternally-expressed in the tammar wallaby; though no ICR2 has been found, the position of TH relative to ICR1 in tammar wallabies resembles humans and cattle (Fig. 2D ).

The genomic context of the orthologous TH/INS locus is shown for the ( A ) house mouse, ( B ) human, ( C ) cattle and ( D ) tammar wallaby. The colour of the gene indicates parental expression; blue is paternal, red is maternal, grey is unknown, white is biallelic. The paternally-methylated ICR1 position is indicated in blue, the maternally-methylated ICR2 position is noted in red. The TH gene is marked with an asterisk. The genomic distance between Th and Ins2 is indicated for the mouse ( A ). The KCNQ1OT1 position in cattle and tammar indicates 500 and 400 bp amplicons that have been detected for this transcript (Ager et al. 2007 ; Robbins et al. 2012 ). Plots below display CpG density as a percentage averaged over 5 kilobase (kb) windows, mb: million base pairs.

The tammar wallaby chimaeric TH-INS transcript is paternally-expressed

The close physical association between the TH and INS genes at the tammar wallaby locus (Fig. 3A ) is exemplified by the production of a previously observed chimaeric TH-INS transcript (Stringer et al. 2012 , 2014 ). RT-PCR, using an INS primer and a TH primer (Figs. 3B, D and 4A ), resulted in two products that differed in size by 274 bp; these transcripts are referred to here as TH-INS1 (GenBank: PP646883) and TH-INS2 (GenBank: PP646884), where the latter includes part of the final exon of the TH gene. Analysis of the DNA sequence in the RT-PCR products showed the presence of a chimaeric junction between TH and INS sequences (Fig. 3C, E ). When appropriate we refer to TH-INS1 and TH-INS 2 collectively as TH-INS .

A The tammar wallaby TH/INS gene locus showing exons as arrowheads indicating the direction of transcription, introns are thinner shaded regions. The blue colouring reflects the paternal expression pattern. Plot below displays CpG density as a percentage averaged over 200 bp windows. B , D Structure of the chimaeric TH-INS1 and TH-INS2 transcripts noting exonic (dark blue) and intronic (light blue) DNA sequences for the TH exon used and the second INS exon. An asterisk indicates the primer used for sequencing of the RT-PCR product and the double dagger indicates the sequence strand assessed. C , E Sanger sequencing chromatogram showing the junction, indicated by a dotted line, between the TH sequence and the INS sequence. Arrows indicate the direction of transcription. F Identification of an antisense transcript at the INS start site (dotted box) in testis transcriptome data with reads split into forward strand (green) and reverse strand (orange). Amplification of the antisense lncRNA was performed by ( G ) 5′ and 3′ RACE using adult testis cDNA. One of the two 3′RACE products (black asterisks) was isolated which encoded ( H ) a non-coding transcript with polyadenylation signal (red) and poly-A tail (green). The sequence of the larger 3′RACE product (red asterisks) was not confirmed.

A , F Primer and SNP positions for allele-specific expression (ASE) analysis of TH-INS and TH . The blue colour of the exons reflects the paternal expression pattern. The TH-INS genotyping primer set (Geno primers) had at least one intronic primer; the cDNA expression primer set (Exp primers) had an intron-spanning primer. B – E , G – J Parent-of-origin-specific transcription of TH-INS and TH . Sanger sequencing chromatograms showing the presence of ( B , G ) the homozygous maternal genotype, ( C , H ) the heterozygous SNP in PY gDNA, and ( D , E , I , J ) the allele present in PY cDNA. K Tabular summary of parent-of-origin-specific gene expression for the different RNA species detected from the TH / INS locus. A mean “mat:pat ratio” value closer to 0 indicates paternal expression (blue shading) while values closer to 0.5 indicate biallelic expression (grey shading). The number of animals is in brackets. “n.d.” indicates not detected. Placenta tissues taken from fetal stage samples, liver and brain taken from PY stage samples. BOM bilaminar omphalopleure, TOM trilaminar omphalopleure. See also, Supplementary Fig. 1 and Supplementary Table 3 .

To test whether TH-INS showed allele-specific expression we genotyped 23 PY for which liver and brain tissue was available and identified three informative animals with SNPs in an INS exon (Fig. 4B ). Transcription of TH-INS was tissue-specific, with the TH-INS1 and TH-INS2 transcripts detected in PY liver, but not brain tissue. Allele-specific expression analysis (Fig. 4A–E ) showed monoallelic paternal transcription of TH-INS1 and skewed paternal transcription of TH-INS2 in the PY liver. TH-INS1 expression was from the paternal allele (Fig. 4K ) in the three animals assessed, where the mat:pat ratio values were 0.01, 0.20 and 0.04. TH-INS2 expression was variable, in the three animals assessed the mat:pat ratios values were 0.18, 0.28 and 0.75. As we expected from previous studies (Agar et al. 2008 , Stringer et al. 2012 ) the INS gene itself (Fig. 4L , Supplementary Fig. 1F–J ) had paternally-skewed expression across three PY livers and had paternally-skewed expression in two PY brain samples (mat:pat ratio values 0.34 and 0.30).

lncINS : a new paternally-expressed long noncoding RNA antisense to INS

In eutherians, some imprinted genes are associated with long non-coding RNAs (lncRNAs): H19 , Kcnq1ot1 and Airn (Wan and Bartolomei 2008 ). Since INS and the associated chimaeric transcript TH-INS1 showed paternal expression, it is possible that there is another lncRNA which regulates the coordinated imprinted expression, as seen in mouse Kcnq1ot1 . In searching for additional elements relevant to the regulation of the INS locus, a new transcript was found (Fig. 3F–H ). This 603 bp transcript (GenBank: PP646882) was discovered in a tammar wallaby adult testis transcriptome dataset (NCBI SRA: DRX012262). This RNA was transcribed from a position proximal to the INS start site in the antisense orientation (Fig. 3F ). The Coding Potential Calculator 2 (Kang et al. 2017 ) gave this transcript a protein coding probability of less than 1%. LncRNAs are defined as RNAs longer than 200 nucleotides that are not translated into functional proteins (Statello et al. 2021 ), here this lncRNA is referred to as lncINS .

Genotyping for SNPs in lncINS identified six informative pre-natal animals of which four were assessed and three informative postnatal animals, out of 12 tested. Allele-specific expression analysis showed lncINS to be monoallelically expressed from the paternal allele in the PY liver (Fig. 4K , Supplementary Fig. 1K–S ) with a mat:pat ratio of 0.09 ± 0.03 ( n  = 3 animals). In placenta lncINS expression was paternally-skewed in the TOM with a mat:pat ratio of 0.24 ± 0.04 ( n  = 4 animals) whilst in BOM expression was biallelic with a mat:pat ratio of 0.53 and 0.44 in n  = 2 animals (Fig. 3K , Supplementary Fig. 1K–S ). Parent-of-origin-specific expression of lncINS was particularly apparent in the TOM tissue of one fetus and the liver tissue of a PY, these animals both had five informative SNPs in lncINS that all were all preferentially expressed from the paternal allele (Supplementary Table 3 ). Further evidence for parent-of-origin-specific, but not allele-specific, expression of lncINS was illustrated by a C/T SNP site in which the T allele was maternally provided to a fetus that had skewed expression of the paternal C allele in the TOM and a PY that inherited a maternal C allele and expressed the paternal T allele in the liver (Supplementary Fig. 1L–S ).

The tammar wallaby has paternal-expression of TH

Since INS , lncINS and TH-INS had paternal expression, it was possible that imprinting might extend to the marsupial TH gene. We examined the allele-specific expression of the TH gene which is maternally-expressed in mice (Golding et al. 2011 ; Jones et al. 2011 ; Okae et al. 2012 ; Bonthuis et al. 2015 ). Genotyping for SNPs in TH identified five informative fetuses of which two were assessed and four informative PYs. Allele-specific expression analysis showed TH was also paternally-expressed (Fig. 3F–K ). Paternal transcription of TH was monoallelic in the PY liver (mat:pat ratio of 0.08 ± 0.08, n  = 4 animals), and paternally-skewed in both BOM and TOM placental tissue (Supplementary Fig. 1A–E ). Providing further evidence for parent-of-origin-specific expression of TH , one of the SNP sites (C/T) showed inheritance of a maternal C allele in one animal and inheritance of a maternal T allele in another animal with the paternal allele expressed in the PY liver in both cases (SNP loc. 11, Supplementary Table 3 ). In contrast, TH expression was biallelic in the PY brain, with a mat:pat ratio for the four animals being 0.39, 0.39, 0.47 and 0.62.

The TH gene is expressed from the paternal allele in the tammar wallaby but from the maternal allele in the mouse. Changes in the parental origins of gene expression are rare. Of the 63 imprinted genes in common between human and mouse, differences in which allele is expressed have only been noted for Wilms’ tumour 1 ( Wt1 ), bladder cancer-associated protein ( Blcap ), and zinc finger imprinted 2 ( Zim2 ) (Tucci et al. 2019 ). Zim2 may be the best example of a change in the parental origins of transcription between species. In humans ZIM2 is paternally-expressed (Murphy et al. 2001 ), whereas in mice Zim2 is maternally-expressed (Kim et al. 2004 ) like TH . ZIM2 is located downstream of paternally expressed gene 3 ( PEG3 ) at a similar distance in humans and in mice (Kim et al. 2004 ). So far no marsupial orthologue has been found for PEG3 or ZIM2 (Suzuki et al. 2011 ; Stringer et al. 2014 ). The change in the imprinting status of Zim2 in the mouse appears to have resulted from an insertional event that placed the Zim1 gene between Peg3 and Zim2 (Kim et al. 2004 ).

The large distance between mouse Th and Ins2 is not the ancestral state of mammals but instead reflects the unique evolutionary path of rodents. The mouse genome is 36.5% transposon-derived and has a high activity of transposable elements, particularly LINEs (Mouse Genome Sequencing Consortium 2002 ; Thybert et al. 2018 ). The activity of transposable elements has varied over time in the primate and rodent lineages, with Muridae showing a recent expansion of LINEs (Thybert et al. 2018 ). While LINEs are present in the expanded region between the rodent Th and Ins(2) genes, particularly in the jerboa, the majority of the DNA separating these genes in mice is made up of LTRs (Shirohzu et al. 2004 ; Lefebvre et al. 2009 ). Though the function of the prominent MYSERV6-int element in this region is unclear, this element is environmentally responsive, and is upregulated in fetal mouse testicular cells after exposure of pregnant mothers to the obesogen tributyltin (Shioda et al. 2022 ).

The repeat-rich region between Th and Ins2 in the mice may serve as a boundary between imprinted domains (Shirohzu et al. 2004 ). But, despite its size, this region does not pose a barrier to imprinting. In the mouse, the silencing effect of the Kcnq1ot1 lncRNA extends from ICR2 some 470 kb, across the genetic region separating Th and Ins2 (Jones and Lefebvre 2009 ). An isoform of Ins2 , Ins2-006 , is regulated by Kcnq1ot1 and maternally-expressed in the E13.5 embryonic mouse head from an alternative promoter 20 kb upstream of the main Ins2 gene (Jones et al. 2011 ). It is not known if Th-Ins2 chimaeric transcripts are produced in the mouse. If a barrier is present between ICR1 and ICR2 then in mice that barrier should be positioned close to Ins2 , between the alternative promoter that drives expression from the maternal isoform and the main promoter from which the paternal Ins2 gene is transcribed (Golding et al. 2011 ).

Variation in the size of the DNA segment separating the INS and TH genes can have phenotypic consequences in humans. A polymorphic region comprising of a variable number of tandem repeats (VNTR) of a 14–15 nucleotide sequence is positioned upstream of the INS gene start site (Bennett and Todd 1996 ). The VNTR alleles occur in three size classes; class III (141–209 repeats) alleles are the largest and have a DNA segment at least 1 kb larger than the class I (26-63 repeats) alleles (Bennett and Todd 1996 ). In addition, a tetranucleotide microsatellite, TH01 , is located within the TH gene and can affect gene expression (Berumen 2023 ). The class III allele is associated with protection against type 1 diabetes but susceptibility to type 2 diabetes when paternally derived (Bennett and Todd 1996 ; Huxtable et al. 2000 ). In the presence of the autoimmune regulator, AIRE, the class III VNTR locus drives expression of insulin at levels three-fold higher than the class I locus in thymic endothelial cells (Cai et al. 2011 ).

There are multiple modes of monoallelic expression (Reinius and Sandberg 2015 ) and we conclude that the tammar wallaby TH/INS gene locus has parent-of-origin-specific gene expression from the paternal allele. Paternal expression of the TH / INS region may result from differential methylation at the distal ICR1 site, the imprint associated with H19 and IGF2 . The imprinting effect of ICR1 could extend to the TH/INS region. Binding of the insulator CTCF to the H19 DMR on the maternal allele changes the chromatin architecture such that IGF2 , the gene adjacent to INS , is maternally-silenced (Smits et al. 2008 ; Hore et al. 2010 ; Llères et al. 2019 ). In mice, H19 and Igf2 are imprinted in both embryonic and extraembryonic tissues while paternal expression of Ins2 is restricted to the yolk sac (Deltour et al. 1995 , 2004 ; Hudson et al. 2010 ).

We expanded the list of transcripts from the marsupial TH/INS locus to include TH , TH-INS1 , TH-INS2 , lncINS , and INS . Imprints are often associated with lncRNAs that can regulate gene expression through various mechanisms (Autuoro et al. 2014 ; Statello et al. 2021 ), the antisense lncRNA is typically expressed from a different parental origin but lncINS is expressed from the same parental origin as INS . The novel marsupial lncINS is not as long as other imprinted lncRNAs in eutherians, this was similar to the marsupial antisense lncRNA in the IGF2R DMR, ALID (Suzuki et al. 2018 ). The degree of paternal transcription was stronger in the PY liver, implying the locus had undergone broader maternal silencing in this tissue. In placental tissue and the PY brain, transcripts from the TH/INS locus showed a mix of biallelic and paternally skewed expression suggesting that regions of the domain are individually regulated.

The levels of transcript expression from the TH/INS locus were not assessed. The abundance of a transcript does not provide any indication of its functional importance, for example lncRNAs are important cellular regulators that are often found at low levels (Seiler et al. 2017 ; Grammatikakis 2022 ). The promiscuity of RNA polymerase can result in “spurious transcription”: a low background level of genome-wide transcription, even of the non-coding DNA (Jensen et al. 2013 ; Wade and Grainger 2018 ). The structure of the transcripts assessed from the TH/INS locus is much more organised than would be expected of spurious transcripts. Detection of known tissue-specific transcripts at low abundance in non-specific cells, without any likely role, has been referred to as “illegitimate transcription” (Chelly et al. 1989 ). Low transcript abundance could make allele-specific expression analysis more subject to gene-intrinsic noise (Kærn et al. 2005 ), but the transcripts from the TH/INS locus had consistent paternal monoallelic expression.

It is unlikely that the TH-INS transcripts are products of transcription termination failure. The chimaeric tammar TH-INS transcripts have a structure consistent with the most frequent form of cis -SAGe ( cis -splicing of adjacent gene) chimaeras which are formed by the uninterrupted transcription of two nearby genes in the same orientation joining the second-to-last exon of the 5′ gene to the second exon of the 3′ gene (Chwalenia et al. 2017 ). Several mechanistic models have been proposed for how the transcriptional termination signal might be omitted from the 5′ gene, including; mutation of the polyA signal, torsional stress and “transcriptional slippage” (Chwalenia et al. 2017 ). The two parental genes that generate a fusion transcript typically have a small intergenic distance (Varley et al. 2014 ). The association of the TH and INS genes in many lineages may have been conserved to allow transcriptional read-through from TH to INS (Hernández-Sánchez et al. 2006 ).

As the TH gene can vary between species in its parental origin of expression (Fig. 5 ), TH could be an “innocent bystander” to the effects of local gene regulation (Duvillié et al. 1998 ; Barlow and Bartolomei 2014 ). If the parental origin of TH expression correlated with the length of the DNA region between the TH and INS genes then all rodents that have inserted repeat sequences separating Th and Ins2 would have maternal expression of Th and all non-rodent therians that have a close physical association of the TH and INS genes would have paternal expression of TH . However, the imprinting status of the KCNQ1OT1 lncRNA is another important variable.

(Left) Cladogram indicating the acquisition of ICR1 in the therian ancestor, acquisition of ICR2 in the eutherian ancestor and the separation of Th and Ins(2) in the rodent lineage. Maternal Th expression in the rodent lineage is indicated by the branch having a red colour. Paternal TH expression in the marsupial lineage is indicated by the branch having a blue colour. The unknown parent-of-origin-specific expression of TH in non-rodent eutherians and ancestral therians is indicated by the grey line colour. (Right) Simplified diagram of the TH/INS region highlighting the unknown parental origin of expression (grey) of TH in non-rodent eutherians, maternal expression (red) of Th in the mouse and paternal expression (blue) of TH in the wallaby. Also indicated is the acquisition of the paternally-methylated (blue) ICR1 and maternally-methylated (red) ICR2. The larger distance between Th and Ins2 in the mouse is indicated by a dotted line between the genes. Species silhouettes include Homo sapiens sapiens by Andrew A. Farke (CC BY 3.0), Murinae by Katy Lawler (CC BY 4.0) and Notamacropus eugenii by Geoff Shaw (CC BY 4.0), courtesy of https://www.phylopic.org .

Maternal expression of Th could be rodent-specific. Placenta-specific imprinted Th isoforms in the mouse are promoted from a rodent LTR located between Th and the adjacent achaete-scute complex homologue 2 gene, Ascl2 (Jones et al. 2011 ). Ascl2 is also maternally-expressed in the mouse placenta (Guillemot et al. 1995 ), but ASCL2 is biallelically-expressed in the human placenta from 12 to 39 weeks gestation (Miyamoto et al. 2002 ). A lack of imprinting at ASCL2 and other neighbouring genes, such as CD81 , in humans could mean that the domain of paternal-silencing by KCNQ1OT1 is shorter in humans, relative to mice, potentially allowing for paternal expression of TH . However, mouse extraembryonic stem cells have maternal expression of Th and biallelic Ascl2 , so it is possible for ASCL2 to be either included or excluded from repression of the paternal locus (Golding et al. 2011 ).

The TH and INS genes lie at the interface of two imprints implicated in developmental pathology. In humans, and other non-rodent therians, whether TH is imprinted is unknown and few studies of INS imprinting have been performed. Mice are commonly used to model the Beckwith–Wiedemann and Silver–Russell syndromes, but some genomic features in this region are specific to rodents. As the mouse and tammar wallaby express TH from different parental alleles, it would be informative to assess parent-of-origin-specific expression in non-rodent therians. Our findings raise the possibility that paternal expression of TH was the ancestral condition in therians (Fig. 5 ) with the parental origins of expression changing in either the eutherian lineage with acquisition of the maternally methylated ICR2 or more recently in the rodent lineage following the extensive insertion of repeat elements between TH and INS .

Data availability

The analysed datasets are available, further information provided in Supplementary Table 1 . Sequences for lncINS (PP646882), TH-INS1 (PP646883), TH-INS2 (PP646884) are available at GenBank ( https://www.ncbi.nlm.nih.gov/genbank/ ).

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Acknowledgements

The authors thank all members of the wallaby research group for helpful discussions and assistance with sampling. We also thank the Hore Lab (The University of Otago, New Zealand) for helpful discussions. The authors acknowledge the use of the services and facilities of the Australian Genome Research Facility. This study was supported by a Melbourne Research Scholarship and the Albert Shimmins postgraduate writing up award to TI and grants from the Australian Research Council to MBR, GS and Tim Hore.

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Teruhito Ishihara

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Trent Newman, Teruhito Ishihara, Geoff Shaw & Marilyn B. Renfree

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TN, TI, GS, and MBR designed the research; TN, TI, GS, and MBR collected the samples; TN and TI performed experiments; TN and MBR wrote the paper with critical feedback from TI and GS.

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Newman, T., Ishihara, T., Shaw, G. et al. The structure of the TH/INS locus and the parental allele expressed are not conserved between mammals. Heredity (2024). https://doi.org/10.1038/s41437-024-00689-y

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Received : 15 June 2023

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Published : 04 June 2024

DOI : https://doi.org/10.1038/s41437-024-00689-y

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