Nettie Stevens and the Discovery of Sex Chromosomes

Daniel and Kelly explore the oft-forgotten scientific contributions of Dr. Nettie Stevens, who discovered that chromosomes are responsible for determining an organism's sex.

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Episode Transcript

Speaker 1 (00:05):
Hello there, friends. Heads up.

Speaker 2 (00:07):
As I'm sure you can tell from the title of
today's show, we're talking about the birds and the bees again,
so keep that in mind as you decide whether or
not you want to listen to this with your kids.

Speaker 1 (00:16):
Also, today, when we.

Speaker 2 (00:18):
Use the word sex, we're specifically referring to gametic sex,
which is to say, we're talking about whether or not
a person produces sperm or eggs.

Speaker 1 (00:26):
Okay, let's get started.

Speaker 2 (00:29):
About two three hundred years ago, Aristotle postulated that babies
come from a mixture of male semen and female blood
that mix together in the uterus. To explain how this
mixture of fluids turned into either a boy or a
girl child, Aristotle pointed to heat. You see, he argued,

(00:49):
all embryos start by developing into boys, but if not
enough heat is present, then that development will stop and
you'll get a girl instead. Five hundred years later, and
we still still hadn't made loads of progress. Gallon, a
famous Greek physician and philosopher, had a much better sense
of human anatomy, but.

Speaker 1 (01:08):
Was still focused on this heat thing.

Speaker 2 (01:11):
Ovaries, he argued, were actually just testes that hadn't experienced
enough heat to make it through the journey to the
outside of the body. By the early nineteen hundreds, we
had learned a lot. Gregor Mandel had done his experiments
in pea plants, so we knew that traits could be
inherited from parents, and we were starting to get an
inkling of where the blueprints for that inheritance were being stored.

(01:35):
We had seen chromosomes inside of cells, but had not
yet tied those chromosomes to the inheritance of specific traits,
and this is where Netti Stevens comes in. Nettie, a
rare PhD holding woman scientist at the start of the
twentieth century, peered into the cells of insects and made
an exciting discovery. One pair of chromosomes were different sizes.

(01:58):
If you got the smaller chromosome, you were a male,
If you got the bigger of the pair, you were
a female. Not only had she discovered what went on
to be called the X and the Y chromosomes, but
this was the first time a particular trait had been
tied to a particular chromosome. Today we talk more about
Nettie Stevens's life and how she came to make this

(02:18):
amazing discovery. Welcome to Daniel and Kelly's Extraordinary Universe.

Speaker 3 (02:36):
Hi. I'm Daniel. I'm a particle physicist, and I'm very
excited to get into the messy questions of biology.

Speaker 1 (02:43):
I'm Kelly Waider Smith.

Speaker 2 (02:44):
I'm a biologist, and wow, these questions really can get
very messy. There's a lot we haven't figured out here.
But I'm excited to talk about the early studying of
how we determine if you end up making sperm or eggs.

Speaker 3 (02:57):
Messy questions, messy answers, messy methid. That's what biology is
all about. Getting gooey with it.

Speaker 1 (03:04):
I like the getting gooey with it part.

Speaker 2 (03:06):
I don't know about the messy methods, but I'll let
that slide.

Speaker 3 (03:10):
I didn't mean sloppy. I mean that sometimes you literally
get gooey. I mean you come home goo all over yourself, right,
You're standing in a dumpster full of goo.

Speaker 1 (03:17):
Yeah.

Speaker 4 (03:17):
No.

Speaker 2 (03:18):
There have been a couple instances where I've been like,
how did I get fish guts in my hair? And
I discovered it later in the day and Zach was
just absolutely appalled, and yeah, gud, you marrying a biologist
is really gross stuff.

Speaker 3 (03:31):
I think it's underappreciated out there by the general public.
How much the methods and the day to day work
decides where you end up in science, because you know, like,
you're interested in the questions of biology, but I'm imagining
you're not answering the deep questions of biology every day.
Mostly you're having fun working with fish guts or whatever,
And so you got to enjoy that bit. And you know,

(03:51):
I spend most of my time writing programs on the computer,
and I enjoy that bit. So it's like, you know,
what kind of messying is do you like? Determines what
kind of science you do. Probably more than your inherent
curiosity about.

Speaker 2 (04:02):
The universe, absolutely, And I don't necessarily know that. We
tell students that enough. Like when I introduced students to
working with me when I was a grad student, I
mentored like a bunch of undergrads, and I'd be like,
look straight up, a bunch of your time is going
to be spent in a room that smells awful, like
a combination of dead fish and formuline, or like staring
and trying to count tiny little items under a microscope.

(04:23):
And if you care about the question, you will love
every second of that. But if you don't care about
the question, you should find a different feel because you're
going to be miserable. And some of them dropped out
not that long after, but it's good to find out
early do you like that kind of stuff or do
you not?

Speaker 3 (04:38):
And sometimes you can care about the question but just
not really enjoy the day to day work of it.
You know. My first experiences in research were like plasma physics,
and I was like, hey, I'm gonna figure out fusion
and save the world. And I definitely still care about that,
but I find vacuum systems and plasma machines annoying and
I did not have a good time that summer. Thank

(05:00):
you to those physicists out there who entered me that summer,
but I was deeply bored.

Speaker 2 (05:06):
You really got to try this stuff out when you're
an undergrad as much as possible. Like I thought I
was gonna love molecular work because it would be like
an episode of like CSI. You know, where they're in
the like fancy labs and they're pipe heetting to find
amazing answers. And I hate pipetting. I'm miserable at it.
My hand's hurt, they get tight. I overthink everything doesn't
matter how great the music I'm listening to as well,

(05:26):
I'm doing it like I cannot get through it, and
so I just I stopped doing molecular work.

Speaker 3 (05:30):
Wait, but do you actually musical montage your way to
an answer? Sometimes you're like, I'm gonna jam through this.
Let's put on the music and dot dot dot there
we are. I love when they do that in TV shows.

Speaker 2 (05:39):
Someone told me like, look, you're overthinking it. If you
just flow, it'll be fine. So pick some music you
can flow to. And I lost like a thousand dollars
because I messed up a bunch of kids because I have.

Speaker 1 (05:51):
To do more than just flow. I'm not a person
who flows.

Speaker 5 (05:53):
I guess.

Speaker 2 (05:55):
But you know, this is a good intro actually, perhaps
even accidental, because the woman that we're talking about today,
there were maybe fifty or more species of insects where
she went through and she like crushed cells, stained cells,
and watched different stages as they divided to produce sperm.
And I read one of her papers and it had
something like two hundred and fifty plates where she had

(06:18):
like very carefully drawn what was happening with chromosomes and
these various stages that must have taken many, many hours
and been incredibly tedious work and counting to track all
the chromosomes and how they were matching up with one another,
and you know, the patients that it must have taken
to even just like extract the game meets out of
like a tiny cricket so that you can look at

(06:39):
them like that takes a lot of skill. So yeah,
she really persisted through a lot of what would have
been very boring work to many of us.

Speaker 1 (06:47):
Maybe she loved it.

Speaker 2 (06:48):
I don't know, but I looked at the plates and
I immediately was like, WHOA.

Speaker 1 (06:52):
I would have been way too bored to do this.

Speaker 3 (06:54):
Maybe she was jamming to the hip music of the
day the whole time, right, sort of like a lost
question in history, what music did famous scientists listen to
while they did all their important work?

Speaker 1 (07:05):
Yeah? Did we have records in the early nineteen hundreds.

Speaker 5 (07:08):
We must have, right, Yeah, I think we did for.

Speaker 1 (07:10):
Sure, jamming to some record.

Speaker 5 (07:12):
Nice.

Speaker 2 (07:13):
I like the idea that that's what was happening. Too
bad she couldn't listen to our podcast.

Speaker 3 (07:18):
Somebody out there write a book about the history of
music listened to by scientists.

Speaker 1 (07:24):
I don't know.

Speaker 2 (07:24):
If that sound career advice, I don't know how big
the audience is for that book.

Speaker 3 (07:29):
I want to read that book, so I don't care
if somebody out there write it.

Speaker 1 (07:32):
Okay, great, sounds good.

Speaker 3 (07:34):
Today we're not talking about music, but we are talking
about pioneering scientists who made incredible discoveries that influence the
way we think about big, important questions in our life.
In this case, big important, messy biological questions.

Speaker 2 (07:48):
Yes, and we're specifically focusing on scientists that most people
have never heard of, despite the fact that they made
absolutely profound discoveries about the way that life works. And
so we pose to our our audience the question what
was Nettie Stevens's big biological discovery? And if you want
to answer our questions, contact us at questions at Danielankelly

(08:11):
dot org and we'll add you to the list and
we'll send you our question before an episode and you
can give us your best guess. All right, let's hear
what our audience came up.

Speaker 1 (08:19):
With this time.

Speaker 4 (08:20):
Nettie Stephens discovered that as long as radioactivity is negligent
a cell, your mechanism will be able to achieve spasis
for a nominal period or duration of time.

Speaker 5 (08:35):
I'll be honest, I've never heard of Nettie Stevens.

Speaker 3 (08:39):
Well, this one's short. I have no idea.

Speaker 6 (08:43):
Did Nettie Stevens invent the Nettie pot that allows you
to irrigate the biological war zone happening in your sinus
cavity as long as you hold your head at the
proper angle. Otherwise you end up with a salty, slimy
soup for lunch.

Speaker 7 (09:00):
My completely uninspired guess is that she discovered that the
Lockness monster is real.

Speaker 2 (09:12):
All right, So to be clear, despite the profound confidence
that we're hearing in that very first explanation, that is
not correct, is.

Speaker 3 (09:21):
That totally manufactured or is that somebody else?

Speaker 4 (09:23):
Yeah?

Speaker 2 (09:23):
No, no, that's totally manufactured hero and made some sort
of joke about like, you know, the more confident you
sound something like that.

Speaker 3 (09:29):
So that sounds like a chat GEPT answer, right, total
confidence and total nonsense.

Speaker 2 (09:34):
Sometimes chat GPT gets it right, but yes, often it's hallucinating,
which this listener was perhaps also doing. She's not associated
with the Nettie Pot. And then we had two listeners
who had never heard of her.

Speaker 3 (09:46):
Well, it sounds like there's a lot of folks out
there who need to know more about Nettie Stevens and
what she contributed to our understanding of the biological world.
So let's go, let's find out. Let's hear all about
Nettie Stephens. So Kellie telling us who was Attie Stevens.

Speaker 2 (10:00):
And I'll do my best to sound confidence so that
even if I'm wrong, everyone will believe it.

Speaker 3 (10:05):
Well, I'm pretty sure you're not an AI. I mean,
I've known you long enough. I think I would have
figured it out by now.

Speaker 2 (10:10):
All right, AI is getting pretty good, all right, So
Nettie and Maria Stevenson. She was born in eighteen sixty
one in Vermont, and she was born to like a
middle class family, and unfortunately her mom died.

Speaker 1 (10:22):
When she was pretty young.

Speaker 2 (10:23):
But she was lucky that she had a father who
really wanted to invest in his daughter's education, and she
also had a sister, and so he sent them to school.
They went to west Ford Academy and she studied to
be a teacher.

Speaker 3 (10:36):
Is this something that was unusual at the time, Like,
did most women go to school? Did most folks living
in middle class Vermont go to school? Or was it
unusual for them to go.

Speaker 2 (10:45):
It was pretty unusual. So training to be a teacher
wasn't super unusual. Training to be a scientist definitely was,
but it was still fairly unusual. And so she leveraged
this early education as a teacher so that through various
points in her life she could teach for a while
to save up money so that she could afford to
follow her dream, which was to become a scientist. And

(11:07):
so she would teach for a while save up money,
and at one point, after saving her money, in eighteen
ninety six, she started at a new school that you know,
maybe you hadn't heard of, called Leland Stanford Junior University.
It ends up becoming Stanford and she gets a bachelor's
and a master's there.

Speaker 3 (11:25):
Wow, And how many women are attending Stanford in the
late eighteen hundreds.

Speaker 1 (11:29):
Not many.

Speaker 2 (11:30):
I don't know the exact number, but there were not many.
And as you'll see, like at one point when she
gets recognized for her amazing contributions, she's on a list
of the top one thousand men in science. Oh so,
and she was one of eighteen women on that list.
So to sort of give you some sense of how

(11:51):
many famous women's scientists there were at the time, there
were eighteen women who broke into this list of one thousand,
and this was towards the end of her career.

Speaker 3 (11:58):
And did she also get married, didn't have a family,
or did she have to choose between those paths.

Speaker 2 (12:03):
So I wasn't able to find a lot of personal
information about Nettie. I haven't been able to find a
biography that people wrote about her, the Encyclopedia Britannica, Wikipedia,
everywhere you go, they pretty much say the same things.
I found a couple scientific papers talking about her early
life and contributions, and they all just sort of like
list off the same facts.

Speaker 3 (12:22):
Sounds like someone who needs to do a deep dive
and write a book about Nettie Stevens. We're like both
projects out the wazoo on this episode today.

Speaker 2 (12:28):
Absolutely, and she was connecting with a lot of major
players in the field at the time, and so I
think there'd be a lot of interesting information to go on.
And maybe like the letters of her advisor, who was
ended up being a famous scientist, we'll talk about him,
like might have mentioned enough where he could get some
more personal details. But anyway, there weren't a lot of
personal details, but No, she did not end up getting
married or having kids, and she ended up being buried

(12:50):
with her dad and her sister. So science was her
life as far as I was.

Speaker 1 (12:54):
Able to tell.

Speaker 2 (12:55):
Married to biology, maybe she had some great hobbies and
had some really cute dogs, but we don't really know.

Speaker 3 (13:01):
Well, it sounds like she had a really fulfilling and
satisfying life, So go Nettie.

Speaker 1 (13:04):
Yes, no, absolutely so.

Speaker 2 (13:06):
Early in her career she identifies two new species of ciliates,
but she ends up wanting to study more sort of
genetic based stuff.

Speaker 3 (13:13):
What's a ciliat?

Speaker 2 (13:14):
Sorry, these are tiny little u carryouts and ciliats are
like little hairs that they have on the outside of them,
and so these hairs sort of are moving frantically to
get them from place to place, and they are teeny
tiny little things. And she's managed to find two new species.

Speaker 3 (13:28):
And how exciting is that to find two new species
of silias? Is that the kind of thing that we
do every day because there's the zillions of them like beetles,
or is it like a big breakthrough or what do
you learn when you name two new species of ciliates.

Speaker 2 (13:39):
There's a lot of cillios to name a new species,
especially today, requires a lot of like precise measurements and
studying the ecology of the animal and coming up with
an argument about why it's different than anything that's been
identified before. So it's really good practice for very careful
measurements of different sort of like organ parts and getting
really good at sort of like drawing things and tracking

(14:01):
sizes and having a good eye for what's different between things.
And so that was probably a really great skill for her.
But I don't think anyone's ever won a Nobel for
identifying a new ciliot.

Speaker 3 (14:11):
Unfortunately, it would be pretty silly to win a Nobel
Prize for ciliots.

Speaker 1 (14:16):
I don't know about.

Speaker 2 (14:17):
Oh silly, it's ah, maybe I am an ai not
getting the jokes.

Speaker 3 (14:23):
Well, you know, I often am criticizing biology as like
just being botany, because I feel like the interesting bit
of science is not let's go out and describe what
we see in the world, But it's the part where
we harmonize it, We put it in context, we understand
the differences, the distinctions, what those trends mean, right, not
just like, hey, here's a list of all the different
silly bits in the world, and we call them ciliots,

(14:45):
you know, And we do this in particle physics also, right,
we have all these particles. We don't understand them, but
we want to or we're asking those questions like why
do we have an electron amuant and a taw. So
when somebody makes a new species, is it always interesting
just having seen it or is it only because it
raises these questions about evolution and the context in history.

Speaker 1 (15:04):
I think it's both.

Speaker 2 (15:05):
And actually I feel like right now, especially in my field,
it's underappreciated when you describe a new species because there
is such an emphasis on like how does this fit
into bigger theories?

Speaker 1 (15:15):
And like that's the kind of stuff that gets to
an NSF grant.

Speaker 2 (15:17):
And to be honest, I feel like we are racing
way ahead on the theory and not stopping to do
enough cataloging so that you actually have the data you
need to test these theories.

Speaker 1 (15:27):
We should have a.

Speaker 2 (15:27):
Whole episode on that. But we're getting off topic, all right.
I would argue that both of those things, the cataloging
and the big theories, you can't do one well without
the other.

Speaker 1 (15:35):
They're built critical.

Speaker 3 (15:36):
You need botany and philosophy to come together in harmony.
All right, But let's get back on track with Nettie.
So she's discovered two new silly kinds of sili. It's
what happens to her next.

Speaker 2 (15:46):
She saves up some money again, and then she ends
up going to get her PhD at Brinmar.

Speaker 3 (15:50):
And she's saving up money because she's paying to do this,
so she's like paying for her education.

Speaker 2 (15:55):
I think she probably had to pay for things like
her housing. I don't know what kind of fellowship they
offered her, but I do know that when she got there,
she was an absolute rock star. And she got the
Brandmar President's European Fellowship, so she got to go to
Naples to work with this famous guy doing genetics work
at the time. So she was like an absolute rock star.
And she wraps up her PhD. And this is when

(16:16):
stuff really starts going. So she starts getting interested in
whether or not chromosomes are what determines if you end
up making sperm or eggs, and she gets a big
grant to answer this question. And when we come back
from the break, we're going to talk about what the
prevailing theories at the time are for what gives you
boys and what gives you girls.

Speaker 1 (16:51):
All right, we're back.

Speaker 2 (16:52):
So let's take a bit of a historical perspective to
figure out where we are. After Nettie Stevens has finished
her PhD. So she finished her pe in nineteen oh three,
so over two hundred years earlier. Anton von Layan Hook
had looked at his sperm underneath the microscope and the
sperm of dogs also, so we knew sperms existed for
over two hundred years.

Speaker 3 (17:12):
And Lewin Hook is the guy who discovered the cell originally, right,
he's like first dude to look in detail at microscopic biology.

Speaker 2 (17:20):
Von Leaywin Hook was not the first one to see cells.
That was Robert Hook. Von Luayne Hook saw little organisms
in pond water. He called them animacules, and he also
did a lot of exploring for little animacules in on
and from his body. So he was the first one
to observe sperm.

Speaker 3 (17:38):
I love the word animacules.

Speaker 1 (17:40):
That's awesome it is, and it's also cute and I.

Speaker 3 (17:43):
Like kees exactly like little tiny animals. How nice? Yeah,
So was he surprised to discover like wiggly things in
his semen?

Speaker 4 (17:51):
Like?

Speaker 3 (17:52):
Is this a big shock to him? Or was he
looking for that.

Speaker 2 (17:55):
Yeah, I think he was a little bit surprised, and
there was some question about whether or not that was
like cantam nation and the like fluid around the sperm
is what was actually important for making babies, And so
I think he was surprised and he wrote it up,
sent it to the Royal Society and turned out, yeah,
that those sperm are important in making.

Speaker 5 (18:14):
Babies, all right, cool, And.

Speaker 2 (18:15):
Then about one hundred and fifty years later we have
the first description of mammalian eggs. So for a while,
actually we use these phrases male sperm and female sperm,
and the idea was that out of the ovaries came
sort of the female equivalent of sperm. And it took
a while before someone actually observed eggs. I think they
had dissected a rabbit to see eggs for the first time.

(18:37):
But so by about eighteen twenty five, we have seen eggs,
we have seen sperm.

Speaker 3 (18:42):
And how do you know what an egg is that
he recognized it, say like, oh, this is obviously the
counterpart to the sperm, like it's in just another cell
in the body.

Speaker 2 (18:49):
Yeah, that's a good question, because it would be another
fifty years before we saw the fusion of sperm and
egg to come together to produce like an embryo. But
I think that it was a series of experiments that
were done on rabbits where they were sort of dissected
at different times, and they observed like the same kind
of cell sort of moving out of the ovaries and
into the uterus. And I think that that's what they

(19:11):
when they were like, Okay, we don't have female semen.
We've got this little thing that like makes a journey
from the ovary into the uterus.

Speaker 1 (19:18):
And I think that they had seen bird.

Speaker 2 (19:20):
Eggs, which sort of gave them like this egg sort
of idea. I believe that that's the history of how
we observed eggs.

Speaker 3 (19:27):
And that sort of the broader context, Like people are
wondering how sex works and how you end up with
boys or girls, and there's already this prevailing concept that
it could be determined by something like microscopic You know,
where are we in like relation to germ theory in
this idea that like there are tiny invisible bits in
biology that could have big macroscopic impact.

Speaker 2 (19:47):
So I think the prevailing theory is that, like, yes,
these things can come together and they can be important
in the production of offspring, but how does that end
up as a boy or a girl is still an
open question, and so one of the theories from like
seventeen forty eight, there was this book by a French
anatomist whose last name was Kuteau, and the book was

(20:08):
called The Art of Having Boys, because obviously that's.

Speaker 1 (20:12):
What you'd want to be doing.

Speaker 2 (20:13):
And the idea was that sex organs come in pairs,
so males have two testes, females have two ovaries, and
so it must be that one testee is important for
making males and one makes females, and they hang at
different heights, and so you should be able to figure
out which one makes boys and which one makes girls.

Speaker 3 (20:32):
And so this is also very logical and also off base.

Speaker 2 (20:37):
Well that this book actually went through four editions, which
is more editions than my book has gone through, so
this was apparently better than anything I've done in my life.
So he actually proposed that if you want boys, you
could figure out which testes makes boys and which one
makes girls, and you could remove the one that makes
girls to make sure.

Speaker 1 (20:53):
You make boys.

Speaker 2 (20:55):
But for the more timid he notes that since there's
one ovary that makes girls, and one ovary that makes boys.
You could instead just have the woman lay on one side,
so gravity will send the sperm to the ovary to
get the child you want.

Speaker 1 (21:08):
Wow, So none of this works. Don't trust best selling authors.

Speaker 3 (21:13):
That's a more general, long standing lesson. Yeah, so people
understand it's something microscopic, but we want to understand the
more detailed mechanism, and that's what people are using microscopes
and dissecting stuff.

Speaker 2 (21:23):
Yes, right, And while we're on the topic of what
ends up giving you boy and girl babies as classically defined.
At the time, nutrition was another popular idea, and so
the idea was that if you are under fed, you'll
produce boys. And I think the argument there is that
sperm they're like smaller and they're chasing to get to
the bigger eggs and so if you're not eating enough,

(21:46):
you produce these smaller sperm things.

Speaker 1 (21:48):
And it's confusing.

Speaker 3 (21:50):
Man. If we had social media back then, there would
been lots of crazy influencers telling people how to have
boys or girls.

Speaker 1 (21:55):
Oh my gosh, so many.

Speaker 2 (21:56):
But you know, to be fair, so like in the
animal Kingdom, whether are not you get an individual who
produces eggs, an individual who produces sperm or an individual
who produces both. So hermaphrodites of different types is actually
very complicated, and so this idea for nutrition wasn't completely crazy.
So like they had taken a bunch of sheep and

(22:16):
they malnourished some and they overfed others, and they ended
up with sixty percent female offspring and forty percent males.
And then there were some what they called lower vertebrates
where they did these experiments and the effects were even
more pronounced.

Speaker 1 (22:31):
And so there are some species where nutrition sort of.

Speaker 2 (22:34):
Plays a role in whether or not you're more likely
to get offspring that make sperm or offspring that make eggs.
And so they had made some observations that were consistent
with this idea, but it just turns out that's not
how most things work, and of course that's not how
humans work.

Speaker 3 (22:46):
All right, So Lowen Hook sees the sperm people discover eggs.
Kutou writes a nonsense book about the art of having boys.
It's understood to be very complicated. How did Nettie get involved,
what was her interest and what did she.

Speaker 2 (22:59):
Cant Taking a very slight step back in like eighteen
sixty five, Gregor Mendel did his pa experiments that you
might have learned about in high school, but it was
a long time ago for me at least. So essentially,
he did all these crosses of pea experiments, and he
discovered that the traits in the like BABP plants were
being inherited from the parents, but it wasn't clear what

(23:20):
material was passing that information from one generation to another.
So he made these amazing contributions to science which were
promptly forgotten about, and nobody looked at it like I
think literally, so a long time ago, when books would
be printed, sometimes you'd have to separate pages with like
a little knife because of the way they were printed.
And so Darwin had Mendel's book on his bookshelf. But

(23:44):
the story, and maybe this is apocryphal, but I've been
told it like five or six times, so I'm gonna
go ahead and share it, was that he hadn't actually
opened up the pages in his book where he would
have learned about this inheritance stuff, So he could have
learned about it, but he didn't. But anyway, okay, Gregor
Mendel does this inhered and stuff. Everybody forgets about it
around eighteen seventy, we first see genetic material, so it's

(24:05):
called nucleon. We don't really know what it does, but
we've now seen genetic material.

Speaker 3 (24:11):
Meaning that we've gone now insize cell. So not just
like here's a sperm, but we're like digging into the
cell and finding the bits that carry that information.

Speaker 1 (24:20):
Yes, yep, exactly.

Speaker 2 (24:21):
But then by the early twentieth century, so around nineteen hundred,
Mendel is rediscovered by a bunch of scientists and we're like,
oh my gosh, okay, traits are inherited from parents. We
have good evidence for that, but what are the blueprints
that are transmitting this information? And so now you can
combine the fact that you've seen this stuff inside of
cells and that feels like maybe that's the stuff that
transmits the information. And so now people are starting to

(24:44):
dig into that. And so this is the scientific background
of where Nettie Stevens jumps in. So in eighteen ninety one,
Herman Vaughn Hanking, he's studying chromosomes. He's noticing that they
almost always pair up, but he notices that there's this
one thing that doesn't hair up, and he calls it
the X element. But he doesn't know what it does.

(25:04):
And this is before the nineteen hundreds when Gregor Mandel
had been sort of rediscovered and his works had been rediscovered,
so people at that time weren't really trying to connect
the stuff that was in the cell to traits that
got inherited across generations. So he's just like, oh, there's
this thing and it kind of acts different than the
other stuff, and he calls it the X element. About
ten years later, Clarence McClung notices the same thing, and

(25:28):
he changes from the like super X many awesome sounding
X element to the accessory chromosome, which is a boring
which is so boring.

Speaker 3 (25:39):
It still has X in the title, right, eccessory chromosome.

Speaker 1 (25:43):
I think we got to talk about your spelling.

Speaker 2 (25:50):
But in nineteen oh two he notices this accessory chromosome
and he says, okay, look, it doesn't seem like all
of the sperm cell are getting it, and so maybe
this is important in determining who becomes a male and
who becomes a female, because that's the most obvious difference
between the organisms that he's studying, his male and female traits.

Speaker 1 (26:11):
And he postulates incorrectly.

Speaker 2 (26:14):
That the males are the one who gets this extra
accessory chromosome. It increases the metabolism of the organism who
gets it, and that's how you get males.

Speaker 3 (26:25):
So he's right on the edge of discovering this, but
he gets it like basically exactly backwards.

Speaker 1 (26:30):
That's right.

Speaker 2 (26:31):
But you know, I think so often when you study
the story of how a scientific discovery comes along, what
you want is like one person who out of the
blue came up with the idea, because.

Speaker 1 (26:40):
That makes for a better story.

Speaker 2 (26:41):
But no, this just like almost all science, is like
a community sort of moving towards an answer, and there's
multiple players sort of along the journey. So McClung is
getting really close, but he gets it in reverse.

Speaker 3 (26:54):
I think that's almost always the case. Like if you
go back and understand like Einstein's work, you see how
many pieces he has pulled together from other folks, and
you see other people publishing the same idea like weeks
after him, done independently. Like it's almost always the case
that science flows as a wave and there's somebody surfing
at the very edge of it, and we like to
write those dramatic stories. It's like single genius in the

(27:16):
dark with a candle, you know, and a blanket to
ward off the Scottish cold. But more often it's a
big community effort.

Speaker 1 (27:23):
Yeah.

Speaker 2 (27:23):
I think that wave is often made of many, many
colleagues who are holding that person up and pushing them forward.
It's not just one person. And that ends up being
the case here too. So Nettie Stevens after her PhD,
she got this big grant to study how those chromosomes
might determine the sex of individuals, and in nineteen oh
five she publishes her seminal study, Studies in Spermatogenesis. And

(27:47):
what she did was she looked at a bunch of
different kinds of insects. So she looked at a species
of termites, a species of sand crickets, croton bugs, and
crucially she looks at meal worm beetles and what she
does for each of them. And this is what we
were talking about earlier. I said there were two hundred
plates where it was meticulously documenting where the chromosomes were
going over time and what was happening. And she was

(28:07):
counting all the chromosomes. So she notes accessory chromosomes in
some of the species that she's looking at. But when
she gets to the mealworm beetle, She's like, Okay, when
you pair up the chromosomes, there is a pair where
you have a big chromosome and a little chromosome. And
I think that the individuals who get the little chromosome
become the males, and the ones that get the big

(28:28):
chromosome become the females. And part of why I think
that is because when you look inside the adult cells,
forget the sperm, let's look at adults. In those adults,
the males have that little chromosome and the females have
that big chromosome. So that must be the thing that
determines sex. And getting that big X that makes you
a female. McClung said, it made you a male, but
that makes you a female.

Speaker 3 (28:48):
And is this what Needdie was studying? What she was
like out to figure out? How did she get interested
in this question?

Speaker 1 (28:54):
This was what she set out to discover.

Speaker 2 (28:56):
I think you know she was a person who was
good at looking at tiny little things and making measurements
and observations on tiny little things, and she was getting
interested in genetics because this field was burgeoning and becoming exciting.
While she was working on her PhD. So like, while
she was working on her PhD, this was the time
when Mendel's rules were being rediscovered concurrent with our discovery

(29:18):
of some genetic material. So trying to tie those things
together became something she was interested in. And actually her
PhD advisor ended up becoming a gigantic name. He's considered
one of the fathers of modern genetics. So he ended
up ultimately establishing like drosophla as a major organism used
for lab work, and he connected a bunch of different

(29:38):
chromosomes to different traits, and so I think it was
sort of like in the air, and she came from
a lab that was sort of interested in these sorts
of questions.

Speaker 3 (29:46):
Well, so this must have been a huge discovery for her,
like to see such a clear answer to this question
that's on everybody's minds.

Speaker 2 (29:54):
Yeah, okay, that's totally true. It should have been a
super big deal. It happened concurrent though, in this the
same year that she published this, Edmund Beecher Wilson, who
was another geneticist who's farther along in his career. He
was looking at a different insects species. He was looking
at the accessory chromosomes and he also said, hey, accessory chromosomes.

(30:16):
These are what makes males and females, and the female
is the one.

Speaker 1 (30:18):
That gets the X.

Speaker 2 (30:20):
So he came up with the same discovery in the
same year. His paper got published a few months before hers.
Oh no, I know, but they had been talking to
each other, and so he references in an updated version
of his paper. He references that, like, hey, Neddie Stevens
found the same thing, and actually she found this little

(30:40):
why thing, And so I believe they had been looking
at insects that had slightly different systems for sex determination.
So in some cases males had the Y and in
some cases males were made by simply not getting anything.
So the females got the extra X and the males
got nothing. They were just sort of missing that information.
And so they had both come up with this at
the same time. They were both it sounds to me

(31:02):
like respectfully communicating their results to one another, and they
just happened to submit And his came out a little
bit before hers, but she's largely credited with being much clearer.
And she went ahead and took that extra step and
looked in the cells of the adults and was like, okay,
this thing that we're seeing in the sperm plays out
in the adults. The adult males have the Y and
the adult females have the X. But I don't actually

(31:25):
feel like it's worth trying to decide, like whose words
were more firm than another, Like, I know we want
one person to be out ahead of the other, but
like they both did really good work, yeah, around the
same time, and this is how science works, and you know,
joint credit seems reasonable to me.

Speaker 3 (31:42):
To me, the issue of these priority disputes is not
who sent in their paper first or who took longer
in review and got it published first. It's just like,
was the work independent? Because if you read somebody else's
paper and then publish based on that, then you shouldn't
get credit for their discovery because you're building on top
of it. But if you figured it out in your
own dank Scottish laboratory, you know, then you figured it

(32:05):
out on your own and if it's in parallel, you
should both get credit. It doesn't matter if you published
six months earlier or six months later. It's an independent
piece of work.

Speaker 2 (32:13):
I agree, But I mean in the way that human
stories always go. You know, people were talking to each other,
and Wilson had been at Bryn Marr right before she
got there, and her PhD advisor kept collaborating with Wilson,
and so like, this is a question they all wanted
to have answered, So they were all kind of working
on it concurrently, and so there was a lot of
discussion between them. Nettie made this really nice, really clear observation.

(32:37):
Wilson also made some great clear observations. So I mean,
to me, it would be great if Nettie Stevens and
Wilson were both known for the discovery of sex chromosomes.
But you know who got the credit.

Speaker 3 (32:48):
I'm guessing it's not Natie Stevens because I'd never heard
of her and neither had the listeners. So then is
it Wilson?

Speaker 1 (32:54):
No, it's Thomas Hunt Morgan. And after the break we'll.

Speaker 8 (33:00):
Talk about why.

Speaker 3 (33:19):
All right, we are back from the break, and Kelly
just dropped a big bomb on us bringing in a
dark horse. Kelly, you can't just bring in a new
character and act three without laying the pipe in act one.
I mean, don't you have you taken screenwriting? One oh one?
Who is this Thomas Hunt Morgan fellow? And why does
he get the credit for Wilson and Stevens independent work.

Speaker 2 (33:38):
Well, I'm going to try to not have my feelings
hurt too much because I had mentioned Thomas Hunt Morgan earlier.

Speaker 5 (33:44):
Oh no, a couple of.

Speaker 2 (33:46):
Times, but you know, we were throwing a lot of
names around, so maybe it didn't stick.

Speaker 1 (33:49):
But he was her PhD advisor.

Speaker 3 (33:51):
So Morgan is Steven's PhD advisor?

Speaker 5 (33:54):
Yes, oh nice.

Speaker 3 (33:56):
No, I totally take it back. You absolutely did lay
the groundwork, but like an excellent novel, I overlooked the
important clues.

Speaker 2 (34:02):
Oh man, maybe I'm the next Agatha Christian exactly.

Speaker 3 (34:07):
So is just the standard case of PhD advisor gets
credits for grad student work? Is their gender stuff at
play here?

Speaker 2 (34:13):
There's definitely sexism at play here. First of all, it's
kind of ironic because Morgan, at the time that Wilson
and Stevens published their result, he was like, not super
sure about this sex chromosome thing. He was like, well,
maybe that's not how it works.

Speaker 1 (34:27):
He still needed to.

Speaker 2 (34:27):
Be convinced at the time these results came out. But
in nineteen oh six there was a conference and both
Morgan and Wilson were invited to give talks about their
theories of how sex is determined. So how you end
up with individuals that make sperman and how you might
end up with individuals that make eggs. But Stevens was
not invited.

Speaker 3 (34:47):
And is Wilson already like a professor and Stevens is
a grad student? Is that how it works?

Speaker 2 (34:51):
Wilson is already a professor, Stevens has finished her PhD,
but she's in a part of her career where she's
having trouble getting the professorship that she deserves. Right, So
actually it will take five maybe seven years for her
to finally get offered a professorship. So she gets offered
a post doc at Carnegie Institute, Washington, and then she

(35:12):
gets to go back to Brent Mahr as a research associate,
but she doesn't get a faculty position. A couple years later,
they offer her that faculty position, but before she can
accept it, she dies of breast cancer.

Speaker 3 (35:24):
Oh gosh, all right, So before we dig into that, Tragy,
let's go back to the conference you were talking about
where her advisor Morgan and her sometimes friendly rival Wilson
both get offered big talks to give their theories of
sex determination. But she doesn't, and she's also the most
junior person of the.

Speaker 2 (35:43):
Three, right right, and dying early is actually part of
the story here.

Speaker 3 (35:46):
Oh wow.

Speaker 2 (35:47):
Wilson and Morgan both go on to become even more
well known scientists. Morgan in particular ends up doing amazing
work on fruitflies, attributing particular genes to particular traits in
these fruitflies. And when Stevens dies, Morgan writes her obituary.

Speaker 3 (36:06):
Oh wow, he.

Speaker 2 (36:06):
Writes her obituary in science and he doesn't get all
of it right.

Speaker 3 (36:11):
Oh gosh, this is like a Morgan character assassination here.
I feel like we need to have somebody from the
Morgan estate onto. But some of this like equal time.

Speaker 1 (36:21):
I mean, okay, so let's take a step back here.

Speaker 2 (36:22):
He was the advisor for Women Scientist, which was very
progressive at the time. I think maybe he wasn't being
aggressive here, but let's dig in a little bit. So
in the obituary he says that Steven's confirmed McClung's hypothesis.
And you might remember that McClung was the guy who
was like, X makes males and he got it exactly wrong.

(36:44):
So she didn't confirm his hypothesis.

Speaker 3 (36:47):
She flipped it on its head.

Speaker 2 (36:49):
She flipped it on his head and then did a
bunch of extra work to make a much more sound argument.
And so here her contributions are getting sort of obscured.
So she's already getting cut out of the conversation. Her
contributions are not being attributed correctly in her obituary.

Speaker 3 (37:04):
But Morgan must have known, right, I mean, obviously, he's
like a big man in his field. He was her advisor.
He's right there, he understands all this stuff. He must
have known what he was doing. Is is there anybody to
see this other than being an intentional obscuring of her
name and deflating of her credit.

Speaker 1 (37:18):
I think that's probably what happened.

Speaker 2 (37:19):
Maybe we should get somebody who's like a Morgan expert
on and maybe they can say, like, oh, this was
during a period where he was drinking too much and
he was just sloppy and something like that. I don't know,
Maybe there's a nicer way to look at it. But
I had a PhD student and they died and I
was writing their obituary, and especially if they were like
one of the first women in their field, I feel

(37:40):
like I would be very careful about how I wrote
that obituary. But so he either was sloppy or he was,
you know, being dishonest.

Speaker 3 (37:49):
But there is a long history of PhD advisors taking
credit for graduate student work, and especially when it's a
male advisor and a female student. And they have lots
of examples of like a man winning the Nobel Prize
for work done by their female graduate student. So it's
definitely not just biology, and at the time I think
it was very common, unfortunately, right.

Speaker 2 (38:09):
And here's another piece of evidence that sort of builds on,
you know, the argument that you just made. Morgan eventually
writes a textbook called The Mechanisms of Genetics, and he
talks about the work that Stevens and Wilson did, but
he doesn't mention I don't think he mentions either of
their names, but he definitely doesn't mention her name, oh Man.
And the way that he wrote it was right before

(38:30):
he talked about the contributions that he made to the field,
and when you read it, you could be forgiven for
thinking that he was on that you know, whole section
just describing his contribution.

Speaker 5 (38:41):
Oh Man.

Speaker 3 (38:42):
Not a fan of Morgan over here, I'm.

Speaker 2 (38:44):
Feeling a little grumpy about Morgan too, and in nineteen
thirty three he goes on to get a Nobel Prize,
not for the discovery of sex determination, but just for
his general work in genetics, and so over time she's
just sort of been forgotten. And so a lot of
people forget about both Wilson and Stevens because Morgan became
such a hot shot, and a lot of people read

(39:06):
this textbook, and I think a lot of them just inferred, oh, okay,
Morgan was the one who figured that out too, And
so over time, Stevens has been forgotten, and so has
Wilson relative to Morgan, and Morgan has gotten a bunch
of the credit.

Speaker 3 (39:18):
I think a lot of people don't appreciate how much
campaigning and politicking there is in getting a Nobel Prize.
Like it's not just you do a bunch of good
science and then you're recognized. It's not some like pure meritocracy.
You know, there's a lot of behind the scenes campaigning
like this person should get the credit, and this person
should get the credit, and this is really important. Like
the folks who get the Nobel Prize are the ones

(39:38):
who bubble up to the top of that campaign and
every year. There's lots of arguments and discussion, and so
wrangling your way into the textbooks and getting the story
told a certain way is definitely a good way to
lay the groundwork for later getting the Nobel Prize. So
I don't know that that's what Morgan was doing, and
Nobel prizes were definitely a newer thing back then, but

(39:59):
you know, writing your into the history of science is
not a new game.

Speaker 2 (40:03):
Yeah, unfortunately, and I think often women aren't playing the game,
or aren't in a position where they can play the
game the same way.

Speaker 3 (40:11):
I saw this happening like in person. When we discovered
that the Higgs boson, we knew that somebody was going
to get the Novel Prize for it, and all of
a sudden, there were lots of theorists giving talks about
their contribution to Higgs theory and the role they played
in bringing it to the discovery because everybody knew it
could be shared between three people, and Higgs was getting it,
but who else was going to get it? So there's

(40:31):
a lot of campaigning, a lot of talks on that topic,
the history of those discoveries, and it was very clear
what was happening.

Speaker 2 (40:37):
I think one day we should talk about your research
in particular. But were you one of those people who
could have campaigned? Were you around during the HAGS time?

Speaker 3 (40:46):
I mean I was on one of the teams. But
one question in the air was were they going to
give it to theorists who came up with the idea
or to experimentalists who discovered it or both. In the end,
they gave it just to theorists, which is still sort
of controversial. And if they had given it to experimentalists,
probably they would have only given it to the heads
of the experiments because the experiments have five thousand people

(41:08):
on it and you can't give them all the Nobel Prize.
That might be one reason why they only gave it
to a theorist, because how do you decide which experimentalist
do give it to? Sort of a frock question. But yeah,
I contributed, I was on those papers. I was there.

Speaker 1 (41:23):
Oh that's exciting.

Speaker 3 (41:23):
Though I don't think I deserve a Nobel Prize for
my contribution. I'm not going to be campaigning for that.
But it was fascinating to see the human side of it,
to see people actively out there arguing that they deserve
the Nobel Prize. And I know that that was influential.

Speaker 2 (41:38):
Okay, yeah, that is an interesting insight I don't think
I had on my radar. Yeah, okay, that's sort of
like the history there. But one of the things that
I wanted to talk about briefly is how different this
story could have been if it wasn't the case that
why chromosomes are a different shape, and so maybe it
would have ended up with the same thing, because there

(41:58):
were some males who justs weren't getting anything, you know,
they weren't getting like a paired chromosome at all, and
that's how they became the males.

Speaker 1 (42:05):
But why chromosomes.

Speaker 2 (42:06):
It turns out, over time they tend to degrade, and
so the idea is that most chromosomes often swap material
at the beginning of myosis. And this process of swapping
allows you to get rid of genes that have kind
of gotten messed up or they've gotten some bad mutations.
But if you have this part of a chromosome that's

(42:26):
now controlling you know, for example, say it has the
code for making testes and for a beard and for
a vast deference, you don't want to be swapping that
and risk getting those male related genes onto the female
related chromosome, so they stop doing that recombination. But that
means that anything else that's also on that chromosome that

(42:49):
doesn't have anything to do with maleness has now not
getting sort of like rejuvenated or removed by this crossing
over process. And so over time those genes, as they
get messed up, we think they sort of like they
fall off because you're not using them anymore. And every
once in a while chromosomes sort of lose bits, and
sometimes that's a problem, sometimes it's not. But over time,
the Y chromosome tends to degenerate, and you also see

(43:12):
this in birds. It's a different chromosome. The males have
Z and Z and the females have Z and W,
and that W chromosome is the one that has started
to degenerate, so it's also started to lose things. So
this observation, like, it seems to me that the reason
we started with sex was because of this weird way
that these chromosomes sort of change shape over time. And

(43:34):
if you hadn't had that clue that these things are
different shapes, it would have been much harder to make
this observation. And I don't know that just seemed interesting
to me while I was going through this research.

Speaker 3 (43:43):
Yeah, because it's sort of macroscopic. I mean, you're zooming in,
you're using the microscope, but you don't need to look
at the actual genome and decode it and like see
the structure of DNA to see that there's something different
between the X and the Y, even just under a microscope.

Speaker 2 (43:56):
And the other thing that's kind of amazing is that
they were able to figure out anything out because the
way that whether or not you get an individual that
produces sperm or eggs or produces both, if they're hermaphrodites,
like the various mechanisms through which those things come about
are super varied. Like reptiles, it does depend on temperature.
And then in the birds, they've got like the opposite,

(44:17):
like we just talked about. The females are the ones
that have the different kinds of chromosomes. And you get
some animals that are sequential hermaphrodites. They've got all the
genetic code that you need to make either decision, and
they can switch between what sets of code they're using.
And while I was reading about sex determination stuff, there
were papers that had titles like sex, chromosome evolution. So

(44:39):
many exceptions to the rules. It's like, there are just
so many different ways that this all works out. It's
kind of amazing we were able to get a foothold,
but we did.

Speaker 3 (44:48):
Yeah, that's incredible. Everything is messy. It's incredible. You can
tell any story. What do we know about the history
of this? You're talking about how over time these degrades.
What is the history and the evolution of sex in biology? Like,
do we know when things went from asexual to having
two genders?

Speaker 2 (45:06):
So I think that there were a number of different transitions.
And I am absolutely not an expert in this. This
would be a whole topic on its own, I think,
But from my reading, what I think I was picking
up was that often when you end up with a transition,
and you end up with offspring that either just have
eggs or just make sperm, that usually starts from a
hermaphroditic ancestor, so you have the code to do both,

(45:30):
and then in some individuals, the set of codes for
male traits is turned off, and for some individuals the
set of codes for female traits gets turned off, and
you end up producing individuals that can no longer produce
both sperm and eggs. They produce only sperm or eggs,
and why that would be beneficial to lose that ability
to do both is maybe a little bit unclear. I

(45:51):
think one of the leading hypotheses is that there's often
not a benefit to reproducing with yourself, So hermaphrodites can
often mix their own sperm and eggs to produce offspring.
But in an evolutionary sense, the extra genetic diversity that
you get by mating with individuals other than yourself has
a huge payoff in terms of being able to like

(46:12):
stay ahead of parasitic infections and stuff. Yeah, and so
I think there's selective pressure for forcing an individual to
mate with other individuals, whereas if you're aromaphroditic, maybe you're like, oh,
it's easier to just mate with me.

Speaker 1 (46:26):
We've all been there.

Speaker 3 (46:27):
I'm going to stay in. It's Friday night and I'm tired.

Speaker 1 (46:30):
That's right, that's right. And that's where the show gots
not appropriate for kids.

Speaker 7 (46:34):
Maybe.

Speaker 3 (46:35):
Well, I think about that because we talk about earliest
common ancestor and how all life on Earth probably has
a single ancestor, but you know, we have gender along
the line at some point, and we didn't have it
early on, which means that at some point it must
have you know, sprung up. And so it's fascinating to
me to think about the history of this and where
it diverges. And maybe one day we'll have the whole

(46:56):
tree of life all the way back through time and
we'll know the answers to all these questions.

Speaker 2 (47:00):
Bacteria started with like conjugation, where they'd just be like
passing over small chunks of genes, and so there's been
a lot of diversity along the way. And without going
into too long of a diatribe about definitions, because to
be honest, I'd like to check my definitions before saying
them publicly. You know, gender, I think is often now
thought of as being different than just do you make
sperm or do you make eggs. It's more about the

(47:23):
strategy that you employ as you go through life, and
so that's a slightly different thing. Just to get our
terms correct. And so today we were specifically talking about
gomedic sex. So do you end up with the genetic
code to make sperm or do you end up with
the genetic code to make eggs?

Speaker 3 (47:36):
All right, so finish the story of Nettie Stevens for
us tell us about how she tragically passes away.

Speaker 2 (47:42):
Yeah, so she finally gets offered that professorship at Bryn Mar,
which she quite clearly earned because two years before she
got this offer. You know, as we mentioned, she was
listed in the one thousand Top Men of Science, so
she was again one of eighteen women. So she was
clearly globally known for the work that she was doing,
and she had one ward for her work on sex chromosomes.

(48:02):
So I think everybody realized that she was making big contributions.
But by the time she was ready to start that professorship,
she died at age fifty of breast cancer. And so
who know, I mean, she still had like a prolific
publication record up until that point. I think she had
published something like forty papers and that was.

Speaker 1 (48:20):
Like, you know what.

Speaker 2 (48:20):
She got her PhD in nineteen oh three. Wow, And
so in maybe a fifteen year period if you include
when she was working on her master she managed to
really knock out a bunch of papers, which to me
is incredible, especially when you consider the tide that she
was working against at the time.

Speaker 3 (48:35):
This is like a Mary Currie type story. Could the
work she was doing somehow have contributed to her breast cancer,
where she using like really dangeruis chemicals and this kind
of stuff in the lab to do her studies. Or
is this just random and bad luck.

Speaker 1 (48:48):
Oh that's interesting.

Speaker 2 (48:49):
I didn't come across anyone who was suggesting that the
work is what ended up killing her. She was using
a lot of different kinds of stains, and so stains
make it easier to see the chromosomes as they and
as they separate. I don't know if any of those
stains were also chriscinogenic, so we're also likely to cause cancer.
It's possible, but I don't know.

Speaker 3 (49:09):
As long as we're just listing possibilities. You know, maybe
Morgan somehow poisoned her. Yes, let's further smirch his character anyway,
that's right.

Speaker 2 (49:20):
I wonder if we're going to get angry emails, But
you know, we'll invite them on the show and they
can defend Morgan if they'd like.

Speaker 3 (49:25):
That would be interesting, exactly if you are Thomas Morgan
the fourth or whatever, and you are grippy at hearing
your great great grandfather's characters merged right in and we
will clear the air.

Speaker 2 (49:34):
But smirched is a great word that's not used nearly
as often as it should be.

Speaker 3 (49:39):
It feels sort of very nineteen hundreds.

Speaker 1 (49:40):
I thought it was er appropriate, absolutely error appropriate.

Speaker 2 (49:44):
So anyway, reading about Nettie made me like totally appreciate
I have had difficult sort of steps in my journey.
I did end up leaving like a master's lab because
of sexual harassment and so like it. You know, hasn't
been one hundred percent easy, but tip to what she.

Speaker 1 (50:00):
Had to go through, then I've had an easy path.

Speaker 2 (50:04):
Anyway, It's just kind of a bummer to hear about
a woman who was doing amazing work, and you know,
I think it would be reasonable to say that she
and Wilson should both jointly be known for this incredible discovery.

Speaker 1 (50:13):
But you know, we.

Speaker 2 (50:14):
All think of it as Morgan's which is just a
bummer on a lot of levels.

Speaker 1 (50:18):
So there you go.

Speaker 3 (50:19):
Here we are pushing gently back against Morgan's politicking to
get himself in the top men of science.

Speaker 2 (50:25):
There we go, Well, he got a noble price, so
I think he won, and we're a little too late,
but hopefully y'all will remember the name Nettie Stevens and
We'll go ahead and share this story with other people
and Nettie will get.

Speaker 1 (50:36):
The credit she deserves.

Speaker 3 (50:37):
Congrats and Nittie on all of your discoveries.

Speaker 1 (50:40):
Way to Go, NTTI.

Speaker 2 (50:48):
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