The biology of gender, from DNA to the brain | Karissa Sanbonmatsu

Summary

This talk explores the complexity of gender identity, especially focusing on the biological, neurological, and epigenetic factors that contribute to being a woman. The speaker, a transgender scientist, discusses how gender is not solely determined by chromosomes, but also by brain development, personal experiences, and societal perceptions. The speech highlights the importance of self-acceptance and the shared experiences of women, while addressing the challenges faced by transgender individuals, especially the high suicide rates. Ultimately, the message emphasizes understanding, connection, and support across all women.

Takeaways

• 🧬 Some women are mosaics, with a mix of chromosome types like XX, XY, or XXX, showing that being a woman isn't solely based on chromosomes.
• 🧠 Female and male brains develop differently in the womb, with a complex mixture of male and female patches in brain structure and activity.
• 🔬 New discoveries in epigenetics are shedding light on how DNA memory and external factors can influence gender identity and expression.
• 👩‍🔬 The speaker shares personal experiences of facing social stigma and isolation as a transgender woman, emphasizing the challenges in scientific environments.
• 🎢 DNA and cell structures are like traveling carnivals, dissolving and being rebuilt daily based on instructions, highlighting the complexity of biological processes.
• 💡 DNA doesn't change sequence often but changes shape, forming knots that act like memory to encode biological responses, including stress management.
• 🐈 Calico cats' fur patterns are a visual representation of DNA decisions, illustrating the significance of epigenetic processes in development.
• 👶 Gender development in the womb occurs in stages, with genitals forming in the first trimester and brains in the second, potentially explaining transgender identities.
• 💪 Support systems like friends, family, and a positive community can help unwind negative DNA effects, promoting resilience and well-being.
• 🌈 The speaker advocates for transgender rights and mental health, encouraging people to seek support and recognizing the pain of isolation faced by marginalized communities.

Q & A

What does the speaker suggest is not a defining factor of being a woman?

The speaker suggests that being a woman is not solely defined by having XX chromosomes, as some women may have different chromosome configurations, such as XY or XXX.

How does the speaker relate neuroscience to the concept of being a woman?

The speaker mentions that neuroscientists have found differences between male and female brains in terms of neuron connectivity, structure, and activity. This suggests that the brain, like a mosaic, may have both male and female 'patches,' contributing to gender identity.

How does the speaker describe the role of DNA in shaping biological functions and memory?

The speaker explains that DNA holds the instructions for cell functions, and its structure can change (form 'knots') due to external factors, such as stress. These changes do not alter the DNA sequence but affect how DNA is read, impacting biological processes and even memory.

What is the speaker’s perspective on gender identity from a biological standpoint?

The speaker believes that gender identity could be influenced by biological factors, including epigenetic changes and brain development in the womb. She describes how precursor genitals and brains can develop differently, potentially leading to transgender identities.

What personal experience does the speaker share regarding her transition?

The speaker shares the social challenges she faced during her gender transition, including judgment and isolation, especially during her first major public talk after transitioning. She also discusses the impact these experiences had on her mental health.

What does the speaker imply about the importance of social support for transgender individuals?

The speaker emphasizes that social support from friends, family, and communities can be life-saving for transgender individuals, noting the high suicide attempt rates among transgender people, especially women of color.

How does the speaker connect epigenetics with relaxation and positive mental health?

The speaker suggests that while much research has focused on negative impacts like stress, new studies are looking into whether positive experiences like relaxation could also influence DNA, possibly leading to beneficial changes.

What is the significance of the calico cat example in the speaker's discussion of DNA and gender?

The calico cat serves as a metaphor for how DNA 'decisions' in the womb create patterns, like the color patches in a calico’s fur. This is used to explain how DNA also contributes to brain and gender development, showing biological diversity within individuals.

What larger point does the speaker make about the question 'What does it mean to be a woman?'

The speaker concludes that the question may not have a singular answer, as the experience of being a woman is diverse and multifaceted. She suggests that becoming a woman involves accepting oneself and recognizing the diversity in others.

What does the speaker hope people will take away from her experience and research?

The speaker hopes people will gain a greater understanding of the complexity of gender and recognize the importance of compassion and support for those who are transgender. She also encourages self-acceptance and mutual acknowledgment of individual identities.

Outlines

00:00

🔬 Understanding Gender Beyond Chromosomes

The paragraph challenges the idea that being a woman is strictly related to having XX chromosomes, introducing the concept of genetic mosaics with varying chromosome patterns. It questions if womanhood is defined by chromosomes, femininity, marriage, or motherhood. The paragraph explores how some theories about brain size and gender differences have been debunked, leading to new discoveries by female neuroscientists showing that the brain is a mosaic, with women having a mix of male and female patches. The paragraph ends by pondering what it truly means to be a woman, given this complexity.

05:01

🧠 DNA, Stress, and Gender Identity

This paragraph discusses the impact of stress on DNA and how traumatic experiences can alter DNA without changing its sequence, by knotting the DNA, which can prevent stress-relief mechanisms from being produced. The speaker reflects on their personal experience during gender transition and how societal judgment contributed to their stress. The speaker mentions that despite professional accomplishments, they faced discrimination, particularly during a talk in Italy. This experience triggered lasting social anxiety, though therapy helped them cope. The paragraph highlights the role of DNA in shaping gender identity and the biological memory of life experiences.

10:07

🧬 DNA Knots and Epigenetics

Here, the speaker delves into the process of DNA knotting and how it functions like a complex code in our bodies. This mechanism enables embryos to develop into different cell types during pregnancy. The speaker mentions their work with Los Alamos Labs, simulating the process of DNA knotting, which helps explain how various physical traits, like those of calico cats, develop. The connection between DNA decisions in brain development and gender formation is also introduced, as well as the possibility that prenatal factors in the speaker’s mother's womb contributed to their transgender identity.

🧘‍♂️ Positive Effects of Relaxation on DNA

In this paragraph, the speaker shifts focus to the potential positive effects of relaxation on DNA. They humorously reference whether mice can meditate like Yoda, drawing a parallel between relaxation and epigenetic changes. The speaker reflects on how support from friends and family has helped them unwind their DNA, so to speak, and regain strength after their experience in Italy. They emphasize the importance of community support, especially for transgender individuals facing adversity, and draw attention to the high suicide rate among transgender people, particularly women of color.

💁‍♀️ What Defines a Woman?

The paragraph concludes with a reflection on what it truly means to be a woman. It touches on how recent research shows differences in male and female brain development in the womb, suggesting that the sense of being a woman may be innate. However, the speaker argues that womanhood is complex and may not be fully captured by biological definitions alone. Instead, they propose that womanhood is about accepting oneself and others for who they truly are, emphasizing shared experiences and mutual recognition. The paragraph ends with an empowering call for self-acceptance and solidarity.

Keywords

💡Gender

Gender refers to the complex interplay between biological, social, and individual identity factors that determine whether someone is perceived as male or female. In the video, the speaker explores how gender is not solely defined by chromosomes, challenging the traditional XX/XY dichotomy, and looks at how brain development and epigenetics may also play a role. The speaker's own experience as a transgender woman adds depth to the discussion of what it means to identify as a woman.

💡Chromosomes

Chromosomes are the structures in cells that carry genetic information. The video challenges the simplistic idea that being a woman is determined by having XX chromosomes, noting that some women have a mix of chromosome types. This concept helps the speaker argue that biological sex is more complex than just chromosomal composition and doesn't solely determine gender identity.

💡Epigenetics

Epigenetics is the study of how external factors influence gene expression without changing the DNA sequence. In the video, the speaker discusses how DNA can change shape in response to life events, such as stress, affecting how it is read and contributing to gender identity formation. The concept helps frame the idea that gender identity may have a biological basis that extends beyond genetics.

💡Neuroscience

Neuroscience is the scientific study of the brain and nervous system. The speaker references neuroscience research showing that male and female brains develop differently in the womb, potentially contributing to a person’s sense of gender identity. These findings are crucial to the speaker's argument that gender may be reflected in brain structure and function, beyond societal roles or expectations.

💡DNA Knots

DNA knots are described as changes in the shape of DNA that can affect how it is read without altering its sequence. In the video, these knots serve as a metaphor for how life's experiences, such as stress or trauma, can imprint themselves on our biology, affecting things like stress response or even gender identity. The speaker highlights that DNA knotting and unknotting act like a programming language, affecting gene expression with 'exquisite precision.'

💡Transgender

Transgender refers to individuals whose gender identity differs from the sex they were assigned at birth. The speaker, a transgender woman, discusses her personal experience transitioning and how it shaped her sense of womanhood. This keyword is central to the video as the speaker uses her journey to explore larger questions about what defines gender and identity.

💡Brain Development

Brain development refers to the processes by which the brain grows and matures, particularly during gestation. The speaker explains how female and male brains develop differently during pregnancy, contributing to the biological underpinnings of gender identity. The concept supports the idea that gender identity may emerge from differences in brain structure and neuron connectivity, which form in the womb.

💡Mosaicism

Mosaicism refers to the presence of two or more genetically different cell lines in the body. The speaker mentions that some women are mosaics, meaning they may have a mix of chromosome types (e.g., XX, XY, XXX). This concept challenges the binary view of sex determination and supports the argument that biological sex and gender are more fluid and complex than traditionally thought.

💡Social Isolation

Social isolation refers to the experience of being excluded or ostracized by others. The speaker shares her own experience of social isolation after transitioning, describing how people stared, chuckled, or avoided her during professional talks. This concept is tied to the broader theme of how societal acceptance (or lack thereof) can impact mental health and identity formation.

💡Support Systems

Support systems are networks of people who provide emotional or practical help. In the video, the speaker credits her recovery from social anxiety and negative experiences during her transition to the support of friends, family, and colleagues. This highlights the importance of community and acceptance in the well-being of transgender individuals, particularly those dealing with societal stigma.

Highlights

The concept of what it means to be a woman is complex and not defined solely by chromosomes.

Some women are mosaics with a mix of chromosomes, such as X, XY, or XXX.

There are significant differences in brain structure, neuron connectivity, and brain activity between male and female brains, according to recent female neuroscientists.

The brain is a mosaic of male and female patches, which challenges traditional gender assumptions.

Epigenetics studies how DNA activity can change without altering the DNA sequence, affecting how cells function.

DNA knots act as memory markers that can be affected by external factors, such as stress, influencing mental and physical health.

The formation of DNA knots plays a crucial role in the body's response to stress and other environmental changes.

During pregnancy, DNA decisions determine whether cells become specific types like blood, brain, or heart cells at different stages of fetal development.

The formation of DNA knots in the womb influences the development of both physical traits and the brain, suggesting a link between brain and gender identity.

A transgender scientist shares her personal journey of feeling misaligned with her body and experiencing social anxiety during her gender transition.

There are complex biological processes behind gender, challenging the notion that gender is solely a social construct.

New research suggests that positive experiences like support and relaxation may also influence DNA in beneficial ways, similar to how stress can negatively affect DNA.

Support networks, friendships, and love can provide strength and hope, potentially reversing negative DNA changes.

Transgender individuals, particularly women of color, face high rates of mental health challenges and need support to prevent tragic outcomes.

Understanding gender requires acknowledging our differences and accepting each other, rather than trying to fit into predefined categories.

Transcripts

So what does it mean to be a woman?

We all have XX chromosomes, right?

Actually, that's not true.

Some women are mosaics.

They have a mix of chromosome types with X, with XY or with XXX.

If it's not just about our chromosomes,

then what is being a woman about?

Being feminine?

Getting married?

Having kids?

You don't have to look far to find fantastic exceptions

to these rules,

but we all share something that makes us women.

Maybe that something is in our brains.

You might have heard theories from last century

about how men are better at math than women

because they have bigger brains.

These theories have been debunked.

The average man has a brain about three times smaller

than the average elephant,

but that doesn't mean

the average man is three times dumber than an elephant ...

or does it?

(Laughter)

There's a new wave of female neuroscientists

that are finding important differences between female and male brains

in neuron connectivity,

in brain structure, in brain activity.

They're finding that the brain is like a patchwork mosaic --

a mixture.

Women have mostly female patches and a few male patches.

With all this new data, what does it mean to be a woman?

This is something that I've been thinking about almost my entire life.

When people learn that I'm a woman who happens to be transgender,

they always ask,

"How do you know you're a woman?"

As a scientist, I'm searching for a biological basis of gender.

I want to understand what makes me me.

New discoveries at the front edge of science

are shedding light on the biomarkers that define gender.

My colleagues and I in genetics, neuroscience, physiology and psychology,

we're trying to figure out exactly how gender works.

These vastly different fields share a common connection --

epigenetics.

In epigenetics, we're studying how DNA activity

can actually radically and permanently change,

even though the sequence stays the same.

DNA is the long, string-like molecule that winds up inside our cells.

There's so much DNA

that it actually gets tangled into these knot-like things --

we'll just call them knots.

So external factors change how those DNA knots are formed.

You can think of it like this:

inside our cells, there's different contraptions building things,

connecting circuits,

doing all the things they need to make life happen.

Here's one that's sort of reading the DNA and making RNA.

And then this one is carrying a huge sac of neurotransmitters

from one end of the brain cell

to the other.

Don't they get hazard pay for this kind of work?

(Laughter)

This one is an entire molecular factory --

some say it's the secret to life.

It's call the ribosome.

I've been studying this since 2001.

One of the stunning things about our cells

is that the components inside them are actually biodegradable.

They dissolve,

and then they're rebuilt each day,

kind of like a traveling carnival

where the rides are taken down and then rebuilt every single day.

A big difference between our cells and the traveling carnival

is that in the carnival,

there are skilled craftsmen that rebuild the rides each day.

In our cells, there are no such skilled craftsmen,

only dumb builder machines

that build whatever's written in the plans,

no matter what those plans say.

Those plans are the DNA.

The instructions for every nook and cranny inside our cells.

If everything in, say, our brain cells

dissolves almost every day,

then how can the brain remember anything past one day?

That's where DNA comes in.

DNA is one of the those things that does not dissolve.

But for DNA to remember that something happened,

it has to change somehow.

We know the change can't be in the sequence;

if it changed sequence all the time,

then we might be growing like, a new ear or a new eyeball every single day.

(Laughter)

So, instead it changes shape,

and that's where those DNA knots come in.

You can think of them like DNA memory.

When something big in our life happens,

like a traumatic childhood event,

stress hormones flood our brain.

The stress hormones don't affect the sequence of DNA,

but they do change the shape.

They affect that part of DNA

with the instructions for molecular machines that reduce stress.

That piece of DNA gets wound up into a knot,

and now the dumb builder machines can't read the plans they need

to build the machines that reduce stress.

That's a mouthful, but it's what's happening on the microscale.

On the macroscale, you practically lose the ability to deal with stress,

and that's bad.

And that's how DNA can remember what happens in the past.

This is what I think was happening to me

when I first started my gender transition.

I knew I was a woman on the inside,

and I wore women's clothes on the outside,

but everyone saw me as a man in a dress.

I felt like no matter how many things I try,

no one would ever really see me as a woman.

In science, your credibility is everything,

and people were snickering in the hallways,

giving me stares,

looks of disgust --

afraid to be near me.

I remember my first big talk after transition.

It was in Italy.

I'd given prestigious talks before,

but this one, I was terrified.

I looked out into the audience,

and the whispers started --

the stares,

the smirks, the chuckles.

To this day, I still have social anxiety around my experience eight years ago.

I lost hope.

Don't worry, I've had therapy so I'm OK --

I'm OK now.

(Laughter)

(Cheers)

(Applause)

But I felt enough is enough:

I'm a scientist,

I have a doctorate in astrophysics,

I've published in the top journals,

in wave-particle interactions, space physics,

nucleic acid biochemistry.

I've actually been trained to get to the bottom of things, so --

(Laughter)

I went online --

(Applause)

So I went online, and I found fascinating research papers.

I learned that these DNA knot things are not always bad.

Actually, the knotting and unknotting --

it's like a complicated computer language.

It programs our bodies with exquisite precision.

So when we get pregnant,

our fertilized eggs grow into newborn babies.

This process requires thousands of DNA decisions to happen.

Should an embryo cell become a blood cell?

A heart cell? A brain cell?

And the decisions happen at different times during pregnancy.

Some in the first trimester, some in the second trimester

and some in the third trimester.

To truly understand DNA decision-making,

we need to see the process of knot formation in atomic detail.

Even the most powerful microscopes can't see this.

What if we tried to simulate these on a computer?

For that we'd need a million computers to do that.

That's exactly what we have at Los Alamos Labs --

a million computers connected in a giant warehouse.

So here we're showing the DNA making up an entire gene

folded into very specific shapes of knots.

For the first time,

my team has simulated an entire gene of DNA --

the largest biomolecular simulation performed to date.

For the first time, we're beginning to understand the unsolved problem

of how hormones trigger the formation of these knots.

DNA knot formation can be seen beautifully in calico cats.

The decision between orange and black

happens early on in the womb,

so that orange-and-black patchy pattern,

it's an exact readout of what happened

when that cat was just a tiny little kitten embryo

inside her mom's womb.

And the patchy pattern actually happens in our brains and in cancer.

It's directly related to intellectual disability and breast cancer.

These DNA decisions also happen in other parts of the body.

It turns out that the precursor genitals transform into either female or male

during the first trimester of pregnancy.

The precursor brains, on the other hand,

transform into female or male during the second trimester of pregnancy.

So the current working model

is that a unique mix in my mom's womb

caused the precursor genitals to transform one way,

but the precursor brain to transform the other way.

Most of epigenetic research

has really focused on stress, anxiety, depression --

kind of a downer,

kind of bad things.

(Laughter)

But nowadays --

the latest stuff --

people are looking at relaxation.

Can that have a positive effect on your DNA?

Right now we're missing key data from mice models.

We know that mice relax,

but could they meditate like the Dalai Lama?

Achieve enlightenment?

Could they move stones with their mind like Jedi Master Yoda?

(Yoda voice): Hm, a Jedi mouse must feel the force flow, hm.

(Laughter)

(Applause)

I wonder if the support I've had since that talk back in Italy

has tried to unwind my DNA.

Having a great circle of friends, supportive parents

and being in a loving relationship

has actually given me strength and hope to help others.

At work I wear a rainbow bracelet.

Sometimes it raises eyebrows, but it also raises awareness.

There's so many transgender people --

especially women of color --

that are just one demeaning comment away from taking their own lives.

Forty percent of us attempt suicide.

If you're listening and you feel like you have no other option,

try to call a friend,

go online or try to get in a support group.

If you're a woman who's not transgender but you know pain of isolation,

of sexual assault --

reach out.

So what does it mean to be a woman?

The latest research is showing

that female and male brains do develop differently in the womb,

possibly giving us females this innate sense of being a woman.

On the other hand,

maybe it's our shared sense of commonality that makes us women.

We come in so many different shapes and sizes

that asking what it means to be a woman may not be the right question.

It's like asking a calico cat what it means to be a calico cat.

Maybe becoming a woman means accepting ourselves

for who we really are

and acknowledging the same in each other.

I see you.

And you've just seen me.

(Applause and cheers)