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

翻译人员: jacks peng 校对人员: Yolanda Zhang

So what does it mean to be a woman?

做女人意味着什么？

We all have XX chromosomes, right?

我们都有XX染色体，对吧？

Actually, that's not true.

事实上，并非如此。

Some women are mosaics.

一些女性的性别特征并不清晰。

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

她们的染色体类型是X， XY和XXY的混合体。

If it's not just about our chromosomes,

如果不只是与我们的染色体有关，

then what is being a woman about?

那么成为女人的要素究竟是什么？

Being feminine?

有女人味？

Getting married?

嫁人？

Having kids?

生小孩？

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

你不需要花很大力气就可以找到

to these rules,

这些规则的例外，

but we all share something that makes us women.

但我们都有让我们成为女人的东西。

Maybe that something is in our brains.

也许这点就在我们的大脑中。

You might have heard theories from last century

你也许听过上个世纪的理论，

about how men are better at math than women

男人的数学比女人要好，

because they have bigger brains.

是因为他们的大脑尺寸更大。

These theories have been debunked.

这些理论背后的真相已经被揭穿，

The average man has a brain about three times smaller

普通人的脑袋比大象的脑袋

than the average elephant,

要小三倍，

but that doesn't mean

但并不意味着

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

普通人比大象要笨上三倍…

or does it?

或者，的确是这样吗？

(Laughter)

（笑声）

There's a new wave of female neuroscientists

有一波新的女性神经科学家

that are finding important differences between female and male brains

正在发现女性和男性的 大脑在神经元连接，

in neuron connectivity,

大脑结构，

in brain structure, in brain activity.

大脑活动方面的重要区别。

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

他们发现大脑就像拼接的马赛克——

a mixture.

是一个混合体。

Women have mostly female patches and a few male patches.

女性拥有大量的 女性模块和少量男性模块。

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

有所有这些新数据背后， 做女人到底意味着什么呢？

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

这几乎是我毕生都在思考的事情。

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

当人们知道我碰巧 是个跨性别者的女人时，

they always ask,

他们总会问，

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

“你怎么知道你是女人？”

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

作为科学家，我致力于 寻找性别的生物学基础。

I want to understand what makes me me.

我想要弄清楚是什么塑造了我。

New discoveries at the front edge of science

前沿科学的新发现

are shedding light on the biomarkers that define gender.

给定义性别的生物标志带来曙光。

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

我和我的同事在遗传学、神经科学、 生理学和心理学方面都有研究，

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

我们试图弄清楚性别是如何起作用的。

These vastly different fields share a common connection --

这些截然不同的领域有共同的连接——

epigenetics.

实验胚胎学。

In epigenetics, we're studying how DNA activity

在实验胚胎学中，我们在研究DNA活动

can actually radically and permanently change,

是如何发生根本和永久性变化的，

even though the sequence stays the same.

即使序列保持不变。

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

DNA是一种缠绕在 我们细胞内的长链分子。

There's so much DNA

DNA的数量十分庞大，

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

以至于它实际上会形成 类似绳结的东西——

we'll just call them knots.

我们就叫它们结吧。

So external factors change how those DNA knots are formed.

外部因素改变了DNA结的形成。

You can think of it like this:

你可以这样想：

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

在我们的细胞里，有各种各样的 精巧装置，它们可以制造东西，

连接回路，

connecting circuits,

doing all the things they need to make life happen.

做所有必要的事情来打造生命体。

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

这里展示的是读取DNA， 制造RNA的过程。

And then this one is carrying a huge sac of neurotransmitters

这个是携带着一个 巨大的神经递质囊

from one end of the brain cell

从脑细胞的一端

to the other.

到另一端。

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

它们做这种工作 难道不会得到危险津贴吗？

(Laughter)

（笑声）

This one is an entire molecular factory --

这是一个完整的分子工厂——

some say it's the secret to life.

有人说这就是生命的密码。

It's call the ribosome.

它叫做核糖体。

I've been studying this since 2001.

我从2001年起就在研究它。

One of the stunning things about our cells

我们的细胞令人惊叹的一点是，

is that the components inside them are actually biodegradable.

细胞内的成分其实是可以生物降解的。

They dissolve,

它们会分解，

然后每天都被重建，

and then they're rebuilt each day,

kind of like a traveling carnival

有点像流动嘉年华，

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

游乐设施每天都被拆除和重建。

A big difference between our cells and the traveling carnival

我们的细胞和流动嘉年华最大的不同是

is that in the carnival,

在嘉年华中，

there are skilled craftsmen that rebuild the rides each day.

每天有技术熟练的工匠 来重建这些游乐设施。

In our cells, there are no such skilled craftsmen,

在我们的细胞中，没有如此熟练的工匠，

only dumb builder machines

只有傻呼呼的建设机器，

that build whatever's written in the plans,

计划中写什么就建什么，

no matter what those plans say.

不管那个计划说的是什么。

Those plans are the DNA.

这些计划就是DNA。

The instructions for every nook and cranny inside our cells.

细胞中对每个细节的指示。

If everything in, say, our brain cells

如果我们大脑中的细胞

几乎每天都在溶解，

dissolves almost every day,

then how can the brain remember anything past one day?

那么大脑如何记住超过一天的事情？

That's where DNA comes in.

DNA在其中起到了关键的作用。

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

DNA是那些不会溶解的部分之一。

But for DNA to remember that something happened,

但要让DNA记得发生的事情，

it has to change somehow.

它得多少做点改变。

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

我们知道改变不能在序列中；

if it changed sequence all the time,

如果它一直在改变序列，

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

那么我们可能每天就会长出 一只新的耳朵，或一个新的眼球。

(Laughter)

（笑声）

So, instead it changes shape,

所以，它改变了形状，

and that's where those DNA knots come in.

形成了DNA结。

You can think of them like DNA memory.

你可以把它想成DNA记忆。

When something big in our life happens,

当生活中发生大事的时候，

like a traumatic childhood event,

比如童年的创伤，

stress hormones flood our brain.

应激激素就会充满大脑。

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

应激激素不会影响DNA的序列，

but they do change the shape.

但它们会改变形状。

They affect that part of DNA

它们通过指令分子机器

with the instructions for molecular machines that reduce stress.

减少压力的方式来影响DNA这一部分。

That piece of DNA gets wound up into a knot,

DNA片段被缠绕成一个结，

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

现在愚蠢的建造机器无法读取到用来

to build the machines that reduce stress.

建造减轻压力的机器的计划。

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

这听起来有点拗口， 但这就是在微观层面发生的事情。

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

从宏观层面上看，你似乎 失去了应对压力的能力，

and that's bad.

这很糟糕。

这就是DNA记得 过去发生的事情的方式。

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

This is what I think was happening to me

我想这就是当我首次 开始我的性别转变时

when I first started my gender transition.

发生在我身上的事情。

I knew I was a woman on the inside,

我知道我内心是个女人，

and I wore women's clothes on the outside,

外表以女装示人，

but everyone saw me as a man in a dress.

但每个人都把我看作 一个穿裙子的男人。

I felt like no matter how many things I try,

我感觉不管我做过多少尝试，

no one would ever really see me as a woman.

也没人会真正把我当作一个女人。

In science, your credibility is everything,

在科学中，你的可信度决定一切。

and people were snickering in the hallways,

人们在走廊里窃笑，

giving me stares,

盯着我看，

looks of disgust --

露出厌恶的表情——

afraid to be near me.

害怕靠近我。

I remember my first big talk after transition.

我还记得在性别转变后 进行的第一次大型演讲。

It was in Italy.

那是在意大利。

I'd given prestigious talks before,

我以前做过口碑不错的演讲，

but this one, I was terrified.

但这次，我害怕了。

I looked out into the audience,

我看着听众，

and the whispers started --

然后窃窃私语开始了——

the stares,

还有陆续而来的凝视，

the smirks, the chuckles.

嘲笑，窃笑。

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

直到今天，我仍然因8年前的 经历而怀有社交焦虑。

I lost hope.

我失去了希望。

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

不要担心，我接受过治疗， 所以我的状态还不错——

I'm OK now.

我现在很好。

（笑声）

(Laughter)

(Cheers)

（欢呼）

(Applause)

（鼓掌）

But I felt enough is enough:

但我觉得已经够了：

I'm a scientist,

我是个科学家，

I have a doctorate in astrophysics,

我有天体物理学博士学位，

I've published in the top journals,

我在顶级期刊中

与波粒相互作用，空间物理， 核酸生物化学相关的领域

in wave-particle interactions, space physics,

nucleic acid biochemistry.

都发表过论文。

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

事实上，我接受过 弄清事情真相的训练，于是——

(Laughter)

（笑声）

I went online --

我上网了——

(Applause)

（鼓掌）

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

于是我上网搜索， 发现了有趣的研究论文。

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

我了解到这些DNA结并非总是坏事。

Actually, the knotting and unknotting --

事实上，打结和解结——

it's like a complicated computer language.

有点像复杂的电脑语言，

It programs our bodies with exquisite precision.

它精确地控制着我们的身体。

So when we get pregnant,

当我们怀孕时，

our fertilized eggs grow into newborn babies.

我们的受精卵可以成长为新生儿。

This process requires thousands of DNA decisions to happen.

这个过程由成千上万个DNA决定。

Should an embryo cell become a blood cell?

胚胎细胞应该变成血细胞吗？

A heart cell? A brain cell?

还是心脏细胞，或者大脑细胞？

And the decisions happen at different times during pregnancy.

这些决定发生在怀孕的不同阶段。

Some in the first trimester, some in the second trimester

有些发生在早期妊娠阶段， 有些发生在中期妊娠，

and some in the third trimester.

有些则发生在晚期。

To truly understand DNA decision-making,

为了真正搞清楚DNA决策原理，

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

我们需要在原子水平观察结的形成。

Even the most powerful microscopes can't see this.

即便是最强大的显微镜 也看不见这个过程。

What if we tried to simulate these on a computer?

如果我们试着在计算机上进行模拟呢？

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

这样一来，我们就需要 上百万台计算机。

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

这正是我们在洛斯阿拉莫斯 实验室所拥有的——

a million computers connected in a giant warehouse.

上百万台计算机彼此连接， 并储存在一个巨大的仓库里。

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

这里我们展示的是组成 整个基因的DNA

folded into very specific shapes of knots.

折叠成了形状非常特殊的结。

For the first time,

这是我的团队

my team has simulated an entire gene of DNA --

在史上首次成功模拟了 整个DNA基因——

the largest biomolecular simulation performed to date.

这是迄今为止最大规模的 生物分子模拟。

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

这是我们第一次开始揭开激素

of how hormones trigger the formation of these knots.

如何引发这些结的形成这一谜团。

DNA knot formation can be seen beautifully in calico cats.

漂亮的DNA结信息可以 在花斑猫上看到。

The decision between orange and black

在橙色和黑色之间的选择

happens early on in the womb,

发生在怀孕早期，

so that orange-and-black patchy pattern,

所以这个橙黑相间的斑片状图案，

it's an exact readout of what happened

准确地描述了这只猫在

when that cat was just a tiny little kitten embryo

母猫子宫里还是

inside her mom's womb.

小猫胚胎时的情况。

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

这种斑块的模式实际上还发生 在我们的大脑和癌症中。

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

它与智力障碍和乳腺癌直接相关。

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

这些DNA决策也发生在 身体的其他部分。

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

事实证明，生殖器前体 会在早期妊娠阶段

during the first trimester of pregnancy.

向男性或女性转变。

The precursor brains, on the other hand,

另一方面，前体大脑细胞

会在中期妊娠阶段转变成不同性别。

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

So the current working model

所以目前的工作模式是，

is that a unique mix in my mom's womb

我母亲子宫里的一个独特的组合

caused the precursor genitals to transform one way,

导致了生殖器前体以一种方式转变，

but the precursor brain to transform the other way.

但大脑前体以另一种方式转变。

Most of epigenetic research

大多数的表现遗传研究

专注于压力，焦虑，抑郁——

has really focused on stress, anxiety, depression --

kind of a downer,

有点令人沮丧，

kind of bad things.

有点糟糕。

(Laughter)

（笑声）

But nowadays --

但如今——

the latest stuff --

最新的情况——

人们在寻找放松。

people are looking at relaxation.

Can that have a positive effect on your DNA?

这会对你的DNA产生积极的影响吗？

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

现在我们缺少来自 老鼠模型的关键数据。

We know that mice relax,

我们知道老鼠会放松，

but could they meditate like the Dalai Lama?

但他们能像喇嘛那样冥想吗？

Achieve enlightenment?

能够有所顿悟吗？

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

它们能像绝地大师尤达 那样用意念搬动石头吗？

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

（模仿尤达的声音）：绝地老鼠 必须能感到原力的流动。

(Laughter)

（笑声）

(Applause)

（鼓掌）

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

我想知道，自从那次在意大利的 演讲之后，我得到的支持

has tried to unwind my DNA.

是否曾试图解开我的DNA之谜。

Having a great circle of friends, supportive parents

有一个很好的朋友圈，支持我的父母，

and being in a loving relationship

以及拥有一个亲密的关系，

has actually given me strength and hope to help others.

实际上给了我力量和希望去帮助别人。

At work I wear a rainbow bracelet.

上班时我戴着彩虹手镯。

Sometimes it raises eyebrows, but it also raises awareness.

有时它会令人侧目， 但也会提高人们的意识。

There's so many transgender people --

有如此多的跨性别人群——

especially women of color --

尤其是有色人种中的女性——

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

仅仅是一个负面评论 就可能导致她们自杀。

Forty percent of us attempt suicide.

有40%我们这样的人会尝试自杀。

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

如果你在听，而且你觉得没有其他选择，

try to call a friend,

试着打电话给一个朋友，

go online or try to get in a support group.

去上网或试着加入互助小组。

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

如果你不是个跨性别的女性， 但你懂得被孤立或者

of sexual assault --

遭受性骚扰的痛苦——

reach out.

记得向他人寻求帮助。

So what does it mean to be a woman?

那么，做女人意味着什么？

The latest research is showing

最新的研究显示

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

女人和男人的大脑 在子宫中的发育是不一样的，

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

可能给了我们女人天生的女人意识。

On the other hand,

另一方面，

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

也许是我们对共性的 意识让我们成为女人。

We come in so many different shapes and sizes

我们生来具有各种不同的体型和身高，

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

问作为女人意味着什么 这样的问题可能并不恰当。

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

就像问花斑猫为什么是花斑猫一样。

Maybe becoming a woman means accepting ourselves

也许作为女人意味着接受

for who we really are

我们到底是谁，

and acknowledging the same in each other.

并承认彼此的共同之处。

I see you.

我看到你了。

And you've just seen me.

你也看到了我。

(Applause and cheers)

（鼓掌和欢呼）