Placeholder Image

字幕列表 影片播放

  • Transcriber: Ivana Korom Reviewer: Krystian Aparta

  • OK.

  • So we are going to start in 1891,

  • when a German scientist was looking through a microscope

  • at insect cells.

  • And he saw something kind of funny.

  • At the center of the cells, there was this dark stuff.

  • No one had ever seen it before.

  • And he noticed that as the cells would multiply and divide,

  • it would go into some of the new cells

  • but not the others.

  • He didn't know what it was, so he gave it a really great name.

  • He called it the "X element."

  • (Laughter)

  • And he was like, "We'll just fill in that X later."

  • And then, fast-forward 10 years later,

  • and there is an American scientist,

  • and she is looking through her microscope,

  • also at insect cells.

  • And she sees something funny.

  • There's more of this dark stuff.

  • And it's kind of tiny,

  • it's hanging out near the X element.

  • And eventually, someone was like,

  • "Well, if that one thing's called X,

  • should we call this other thing Y?"

  • And like that, (Snaps fingers)

  • the sex chromosomes had been discovered.

  • So chromosomes,

  • you probably all know what they are,

  • but I will tell you anyways.

  • They're made up of DNA --

  • everything has it, it's the blueprint of life,

  • we've got rats, we've got trees,

  • we've got insects, we've got humans.

  • And in the case of human chromosomes,

  • geneticist Melissa Wilson broke it down for me like this.

  • (Audio) Melissa Wilson: Typically, you'll get one copy of every chromosome

  • from your genetic mom

  • and one copy of every chromosome from your genetic dad,

  • and we have 22 of these

  • that you get one copy from mom and one copy from dad.

  • And then there's a 23rd pair, X and Y.

  • Molly Webster: So while all the other chromosomes are numbered,

  • one through 22,

  • we do not call X and Y 23.

  • I like to think that they are waiting for, like, a LeBron James to come along.

  • But in this instance, they were like,

  • "We're just going to keep the letters,

  • and then we'll give them a title."

  • They called them the sex chromosomes.

  • Now I would wager that in the United States,

  • these are the most well-known chromosomes

  • for one simple fact:

  • that we say X equals "girl," and Y equals "boy" --

  • that they are responsible for sex.

  • And -- and I had to learn this --

  • but when I'm talking about "sex" here,

  • I'm talking about the way biology gives us gonads,

  • which are our ovaries and our testes --

  • I'm not talking about gender, which is how we identify.

  • And so, as a reporter at the show --

  • "Radiolab," the audio documentary program I work for --

  • I was like, what's up with these sex chromosomes?

  • You know, that's kind of my job, I think things are weird,

  • and then I get to call people about them

  • and ask questions, and then hopefully they answer.

  • And in this case, a lot of people answered.

  • And in the two years I had of reporting on X and Y,

  • as part of "Gonads," the series on sex and gender

  • I ended up doing for "Radiolab,"

  • I found out that these two chromosomes live in a world that is unexpected,

  • a little unsettling;

  • where things that I thought were facts

  • were, like, twisted in ways I hadn't seen before.

  • And the world goes so far beyond the boundaries of sex,

  • I was like,

  • "Maybe we should all talk about this."

  • So, you're you all,

  • we're all going to talk about it.

  • And for me,

  • the true story of X and Y starts with their name.

  • So within years of being discovered,

  • these two little chromosomes had acquired more than 10 different names.

  • There was diplosome and heterochromosome

  • and idiochromosome,

  • and most of the names had to do with their structure, their shape,

  • their size.

  • And then there was "sex chromosome,"

  • which they had been given because of the fact

  • that we had started seeing that the X would go with the females,

  • and the Y would often go with the males.

  • But scientists were like,

  • "Do we really want to call them sex chromosomes?"

  • And science historian Sarah Richardson is the one who told me this story.

  • (Audio) Sarah Richardson: For three decades, scientists were like,

  • "You should not call them the sex chromosomes.

  • The X and Y have many functions,

  • and you wouldn't assume that a single chromosome

  • controls a single trait.

  • Imagine calling one chromosome the 'urogenital chromosome,'

  • or the 'liver chromosome.'"

  • MW: Scientists, if you dig into the history --

  • it's really cool, you should --

  • were hesitant to, like, commit to such a specific name

  • and such a powerfully connotated name.

  • There was a fear that it would actually be really limiting --

  • maybe to science, maybe to society --

  • but the fear was in the room.

  • And you can see they ended up getting "sex chromosome" --

  • it's like a pretty juicy title,

  • it popularized genetics, you know?

  • But in the 100-year history since we settled on that name,

  • you can see it starts to get a little complicated.

  • So around 1960 --

  • this is going to be our first stop

  • on the complicated world of the sex chromosomes --

  • so around 1960,

  • we had discovered that you could be XYY.

  • They discovered an XYY man.

  • And to digress a little here,

  • it turns out that the model of "X equals girl and Y equals boy"

  • is really simplistic.

  • You can actually be a whole bunch of different combinations of X and Y,

  • giving you, like, different types of biological sex.

  • You could be two Xs and two Ys together.

  • You could be four Xs, you could be five Xs,

  • you could be XO.

  • And so I thought that was pretty crazy,

  • because I was like,

  • "Wow, this really upends a model of biological sex

  • I think most of us in this room have been taught."

  • So a few years after they realized that you can be XYY,

  • researchers go to a prison in Scotland,

  • and they do genetic analysis of a bunch of the male prisoners.

  • And they find a number of people who are XYY.

  • And according to Sarah:

  • (Audio) SR: They just rushed to publish a theory

  • suggesting that this extra Y chromosome

  • could explain criminality in some men.

  • MW: Yeah.

  • So the logic goes like this:

  • By this point, we're thinking Y is male.

  • We think male is aggressive,

  • so Y must be aggression.

  • If you've got an extra Y, you must be crazy.

  • And like, we went nuts with this theory.

  • We called it the supermale,

  • they started scanning more prisoners,

  • serial killers, boys.

  • And in all seriousness,

  • there was actually a suggestion that we consider aborting XYY fetuses.

  • So in 1980,

  • this theory pretty much toppled, for a number of reasons.

  • One,

  • there had been this really large study

  • that basically showed there was no connection

  • between Y and violence,

  • I think we all saw that coming.

  • And then, there was one other thing.

  • (Audio) SR: Going back and looking at those original findings

  • in that high-security psychiatric institution,

  • they had also found a high number of individuals

  • with an extra X chromosome.

  • So these are XXY, as opposed to XYY.

  • (Audio) MW: Really?

  • (Audio) SR: Yeah. Now, they never claimed

  • that the individuals with an extra X chromosome

  • were superfemales.

  • They never investigated whether they had higher rates of violence.

  • MW: Seems like kind of an oversight.

  • I don't know.

  • But I think it's interesting,

  • because what you see is if you start looking at these chromosomes

  • through the lens of sex,

  • what naturally falls in place behind

  • is we look at them through the lens of gender,

  • and the traits that we associate with gender.

  • So men were violent,

  • and Y explained why they were in prison.

  • The X did not do that,

  • because like, you know, what's X?

  • We don't associate it with violence.

  • And while we don't believe in supermales today --

  • God, I hope we don't --

  • we don't believe in supermales today,

  • there is a very similar conversation that's still happening

  • around inherent violence in boys and biology.

  • So my next stop on the weird world of X and Y,

  • or things feeling a little topsy-turvy, is 1985.

  • The World University Games were set to happen in Japan,

  • and the Spanish hurdler María José Martínez-Patiño was scheduled to run.

  • She was like a hot shot, a rising superstar.

  • And the night before her race, they had her DNA scanned.

  • Now at the time, this was a thing that they were doing,

  • because they were like,

  • "OK, we don't want men covertly racing as women,

  • so we're going to scan the women

  • and make sure all their Xs line up."

  • And so I heard this story from Ruth Padawer

  • who was a New York Times Magazine reporter

  • and she reported on María.

  • (Audio) Ruth Padawer: So they tell her the chromosome test results were abnormal.

  • Although on the outside, she was fully female,

  • she had XY chromosomes and these internal testes.

  • MW: They were like,

  • "We hate to break it to you, María, but you're actually a dude.

  • You can't race with the ladies."

  • (Audio) RP: And so she's thrown off the national team,

  • she's expelled from the athletics residence,

  • she's denied her scholarship,

  • a bunch of her friends dump her,

  • fellow athletes abandon her,

  • she loses her medals, her records are revoked.

  • MW: So it turns out --

  • remember when I told you

  • you can be a bunch of different combinations of X and Y --

  • you can also be XY and be female.

  • You can be XX and male.

  • In María's case, she was something called androgen insensitive.

  • Which means that she did have some sort of internal testes --

  • they were making testosterone --

  • but her body couldn't use it.

  • And so if you thought of testosterone as, like, a superpower,

  • she was not benefiting from it.

  • And so eventually,

  • sports authorities, like, let her back in,

  • but her career was done.

  • And in this instance you see how,

  • if you assign sex to a specific place in the body,

  • or at least, like, this is what I saw, right?

  • If you assign sex to a specific place in the body,

  • it somehow makes us think that we can go into a body,

  • look at a specific place

  • and tell someone we know something more about them

  • than they know about themselves.

  • And that feels terrifying to me.

  • And we don't genetically test female athletes anymore,

  • but you can see very similar conversations happening

  • when we talk about testosterone in sports,

  • you can also see it in suggestions that we take transgender individuals

  • and we genetically analyze them and we tell them who they are.

  • That is real,

  • that is a conversation that has happened recently.

  • The last place that I'll share with you

  • where these chromosomes got complicated for me

  • is this one thing that Melissa told me.

  • (Audio) Wilson: You can't survive without an X chromosome.

  • No matter your gonads, no matter your identity,

  • every single human being has to have an X chromosome,

  • because without one, the rest of your body doesn't develop.

  • MW: Why do we call this the female chromosome?

  • OK, this is something I had never though about,

  • but literally, every single person in this audience has an X chromosome,

  • I'm not lying.

  • Every single person on the planet has an X chromosome,