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wherever you get your podcasts Okay,

1:10

so technically Warren Booth is

1:12

an entomologist his main research

1:14

focus and the stuff he gets funding for

1:16

looks at bugs But

1:19

he has this hobby my

1:22

little side project is is Maintaining

1:25

120 snakes in my basement and I breathe snakes

1:27

having keeping him breathing snakes for about 30 years

1:30

So back in 2010 or so Warren got a

1:32

phone call I was contacted by someone asking if

1:34

I could do a paternity test on a snake

1:37

This person's boa constrictor had had a

1:39

bunch of special babies Like they were

1:41

born with a kind of albinism that

1:44

made them pink and yellow Which is

1:46

pretty but also apparently and

1:48

a valuable Warren says they can

1:50

go for for thousands of dollars So

1:53

the snakes owner wanted to know like who

1:55

had fathered these expensive babies And

1:58

even though Warren at the time was doing his postdoc

2:00

on bugs, he had

2:02

developed this scientific tool that could

2:05

actually answer this exact question. I

2:07

thought my career was over because there was no faculty

2:09

jobs coming up. And to be asked

2:12

to do paternity tests on a snake, I thought was just

2:14

the end of the world. But Warren

2:16

figured, sure, let me

2:18

figure out who this snake's dad is. Why

2:21

not? So I ran the tests and it

2:23

turned out there was no father. It

2:26

was Parthenogenesis. It

2:29

is a form of asexual reproduction.

2:32

In this particular case, it's where an

2:34

animal that normally goes through sexual

2:37

reproduction decides to do

2:39

something a little more DIY, no

2:41

male involved. So a female creates

2:43

an egg and then instead of that

2:45

egg merging with a sperm, it seems

2:48

like it somehow merges with another egg-like

2:50

cell. And it's not cloning. It's

2:52

that the egg and the egg-like cell

2:54

have a mixed-up version of the female's

2:57

genes. But the

2:59

end result is that the female makes

3:01

an embryo all by herself. And

3:04

Warren was pretty surprised to see that

3:06

this had happened with this boa. As

3:08

he understood it, this form of

3:10

Parthenogenesis was pretty rare in vertebrates.

3:13

It was unusual enough and special enough

3:16

that Warren actually figured that it was worth

3:18

writing up. He thought, people

3:20

should know that a boa constrictor can

3:22

do this. So even

3:24

though he was a bug guy, he pulled

3:27

together a scientific article about this

3:29

woman's snake. So

3:31

I'm writing the paper to publish this

3:34

and she calls me up and says she did it again. A

3:37

year later there were 10 or 12 more babies. A

3:40

dozen more fatherless snakes. Which

3:42

means that not only was

3:44

this the first documented case of Parthenogenesis

3:47

in a boa constrictor, but the

3:49

boa had done this unusual thing. And

3:53

this paper kind of blew up. It went

3:55

worldwide. The First phone call I

3:57

got was from the BBC. It

4:00

just went crazy from there and as a

4:02

result of that I then canada known for

4:04

doing this passage genesis work and snakes are

4:07

literally A couple of weeks later somebody else

4:09

contact me a bypass the genesis in a

4:11

different species snakes and not so continued. In

4:14

a almost monthly since then. All

4:16

these other examples of parthenogenetic up tiles

4:18

started coming out of the snake holes.

4:21

Just. Yesterday I was contacted by some

4:23

a potential case in Florida. Pine snakes

4:25

either freezer full apart in age and

4:27

sustaining. I'd I'd one hundred and something

4:29

from with and is interesting and Freezer.

4:32

Just your average ordinary researcher. With that

4:34

say simple a snakes and at freezer

4:36

full of present tense. The.

4:39

The point is. Worn. Realize that

4:41

a lot more species are capable of

4:43

patterns genesis the need originally thought. And

4:46

it's not just reptiles Saturday. Sorry

4:49

about the pregnancy rate. Earlier this

4:51

year a stingray name's Charlotte went

4:53

viral to see that pregnant seemingly

4:56

with no mail involved. who's the

4:58

daddy. Who's the daddy? The sixty

5:00

one thousand dollar question shows that

5:02

that is sleeping Charlotte His dad.

5:06

And it's in a prison. Douglass keep

5:09

popping and species of birds. Sites.

5:11

Raise lizards, crocodiles,

5:14

Like examples and every bird a

5:16

big plot and basically except for

5:18

mammals. And this isn't

5:20

totally new like. Researchers have known for

5:22

decades the different classes of vertebrates

5:25

were able to do parthenogenesis. But.

5:27

They're starting to think that they. Really

5:29

underestimated how com and it is.

5:32

So. Then the next question is. Is

5:35

a lot of animals can do this. But.

5:37

Does that mean what we're interested in? I

5:40

can understand why it's happening and and on

5:42

what are the implications of? This.

5:46

Unexplainable. I'm for think attend and

5:48

say on the So We look

5:50

at said weird wonderful phenomenon apartments

5:53

Genesis and we try to figure

5:55

out why it happens. I

6:13

sort of accidentally stumbled

6:16

into a study on

6:18

parthenogenesis. Fifteen died in

6:20

is a biologist who studies sites

6:22

and raise and she was trying

6:24

to study some zebra sharks and

6:26

an aquarium and Australia when this

6:28

one zebra zoc named we only

6:30

had. Not one, but. Two

6:33

rounds of parthenogenetic eggs.

6:36

Parthenogenesis. Had been observed

6:38

in the species before. But what

6:41

was special about Leoni was it

6:43

should senate switching things up because

6:45

in the past. She'd. Had

6:48

some babies the old fashioned way. like

6:50

sexual. Reproduction. And

6:52

now. She was going it alone. And

6:55

while this kinda thing have been seen

6:57

and insects, Christine was really surprised to

6:59

see it in a shock. What?

7:01

Had never been. Documented before in

7:04

any shot. At this

7:06

time was an animal switching.

7:08

Between reproducing sexually to

7:10

then reproducing path in.

7:12

A genetically Because it all

7:14

the previous cases the documents

7:17

were of animals who. Essentially

7:20

reached. Maturity in an

7:22

aquarium setting and had never

7:24

had exposure to mail. Pristine.

7:27

Started thinking. Leoni the

7:29

shark seem to be able to

7:31

toggle parthenogenesis on and off. The.

7:33

Flipping. A switch basically. so

7:36

perhaps rather than it just.

7:38

Being this kind of anomalous, things

7:40

like a mistake which was the

7:43

prevailing concept know perhaps this is

7:45

actually some sort of strategy and

7:47

this is all speculate as. But.

7:50

The Hypothesis Secrecy is playing with

7:52

his The Evolutionary Go and have

7:54

a Hail Mary pass. so

7:58

far as i think we'll need Sexual

8:00

reproduction is a better option than

8:02

parthenogenesis, right? It gives her babies

8:04

more diverse genes, and that makes

8:07

them stronger. But

8:09

if there are no males around,

8:11

and sexual reproduction is off the

8:13

table, then maybe something is triggered

8:15

in some animals' bodies, and they're

8:18

basically like, well,

8:20

I might as well do something. So

8:23

this hockey great wing, Gretzky famously

8:25

said, you miss 100% of

8:29

the shots you don't take. We're

8:31

just going all in on sports metaphors today. But

8:34

so, in some species, like chickens, parthenogenesis

8:37

takes care of another problem.

8:40

In that case, what happens is that,

8:43

you know, if you don't have a male, you can

8:45

make them. A mom making a son

8:47

that she then mates with is uncomfortably

8:50

incestuous, but maybe

8:52

it's better than nothing. And in

8:55

the case of sharks, the babies that come out

8:57

of these parthenogenic births are all

8:59

females, so the females can't make themselves

9:01

a mate in this way. But

9:04

Christine still thinks that parthenogenesis could be

9:07

useful here. My current thinking

9:09

is that what the adaptation is,

9:11

is that it essentially extends the

9:13

life of the egg cell. If

9:16

the egg cell stays inside the mom and no

9:18

male shows up, the egg cell dies with the

9:20

mother. There's a 100% chance

9:22

that she doesn't reproduce. You miss 100% of

9:25

the shots you don't take. But

9:28

if the mom turns that egg into a

9:30

female baby, then that

9:32

female could outlive her and carry

9:35

their genetic information out

9:37

into the world. And then

9:39

hopefully, the female would then find

9:41

a male to reproduce

9:44

with to then maintain that

9:46

genetic diversity. But

9:49

most of the examples that scientists are

9:51

working from are animals in captivity, right?

9:54

Like sharks in aquariums, chickens in

9:56

cages, like scenarios where females

9:58

are kept apart from males. because of

10:00

human intervention. Which

10:02

left me wondering, like are

10:05

there similar situations in nature where

10:07

females are kept separate from males for

10:09

long periods of time? And

10:11

Christine says, maybe. I

10:14

mean, the ocean is a massive place. These

10:16

are animals that are migrating thousands

10:18

of miles every year. They

10:21

have their mechanisms to come and find

10:23

each other for sexual reproduction, but maybe

10:25

they get lost occasionally. And there's

10:27

kind of a bigger picture question here too. I

10:30

mean, one of my research interests being

10:32

for the evolution and maintenance of biodiversity.

10:35

And so these are questions that go

10:37

back into time. How did new

10:39

species come about? One

10:41

method researchers talk about is when a

10:44

species gets blown onto

10:46

an island, say, or just moves into a

10:48

new area and there are no males around

10:50

for a while. Could they

10:52

default to parthenogenesis to kind of extend

10:54

their timeline for a bit? I

10:57

think there's some interesting concepts

10:59

there to explore. But again, before

11:01

we get too excited with all

11:03

this, like Christine is very clear

11:05

that we need a lot

11:07

more evidence here, especially evidence

11:10

of animals doing parthenogenesis in the

11:12

wild, which we currently

11:14

have very little of. So

11:16

this is very much speculating, but

11:19

it's a compelling idea, right? To

11:22

me, yes. To others,

11:24

maybe less so. After

11:27

the break, Lauren Booth is skeptical

11:30

that parthenogenesis is a strategic

11:33

tool. He's got a bunch

11:35

of super weird snakes to explain why. Support

11:40

for Unexplainable comes from Bambas. And

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not available in all states of situations. John,

15:55

you are not the father. Worn

15:59

this the guy we met at the beginning with all

16:01

the snakes in his basement, he

16:03

does think parthenogenesis is interesting. They

16:06

have them fully by Christine's hypothesis

16:08

that vertebrates use parthenogenesis as a

16:10

Hail Mary pass to keep their

16:12

genes going for another generation. And

16:15

he's skeptical, in part, because of

16:17

his own firsthand experience with

16:19

parthenogenetic baby snakes. So

16:22

take that snake that he wrote that first paper

16:24

about, the boba constrictor that

16:26

had two litters of

16:28

beautiful albino babies. Warren

16:31

was curious about those babies. I

16:33

asked for one because I wanted to be able to see

16:35

if we could raise it up. So the

16:37

owner sent Warren one of the parthenogenetic

16:39

baby snakes in the mail. Yeah,

16:41

you can just overnight them with FedEx and

16:44

insulate his styrofoam boxes with heat packs. It's

16:46

like the stork. Instead of

16:48

baby humans, it brought baby snakes. And

16:51

if sometimes you had to go pick up your baby

16:53

at a very inconvenient location because you weren't home to

16:55

sign for it. Anyway,

16:59

this baby snake came by FedEx, and

17:01

Warren was able to raise it. But

17:04

it was kind of odd. It

17:06

was shorter than similar age, sexually

17:08

produced. Individuals, it behaved

17:11

slightly differently. It kind of tweaked.

17:14

And when it reproduced, it behaved totally

17:16

differently. The snake was able

17:18

to get pregnant, but it was super weird

17:20

about it. Normally,

17:23

Warren's snakes are kept in a tank with

17:25

a hotter end and a cooler end. And

17:27

when they're pregnant, they're kind of bask

17:29

in the heat, but not this

17:31

snake. It stayed at the cool end instead of

17:33

being under the heat. The gestation

17:36

was longer than expected. And when it

17:38

produced, it produced a pretty

17:40

small litter, but half of those offspring were spent.

17:43

And then there was the parthenogenetic ball

17:45

python family from the UK. There

17:48

was a snake that had been

17:50

born by parthenogenesis, and her daughter

17:52

also born by parthenogenesis, so first

17:55

and second generation parthenogens. And

17:57

they were both sent to Warren, who tried to raise

17:59

them. That second generation Parthenogen

18:02

didn't do well and it died

18:04

relatively quickly. Rest in peace little

18:06

snake. But um, the

18:08

mother? She produced a clutch

18:10

of eggs. This time there was

18:12

a male in the picture, so her eggs were

18:14

fertilized. But much like

18:17

the albino boa constrictor baby from

18:19

before, this snake was also super

18:21

weird about things. She sat

18:23

in the cool end instead of the hot end. She produced

18:26

six eggs, which five essentially

18:28

went bad within the first couple of

18:31

days. Warren

18:33

says this all fits a bigger pattern that he's

18:35

noticed. A lot of Parthenogens

18:38

just die as embryos. And

18:40

those that do make it don't do all

18:42

that well. In his

18:44

experience, Parthenogens die within a handful

18:46

of years before reproducing. And

18:49

this actually makes sense if you look at

18:51

the genetics here. Because with

18:54

the snakes that Warren was working with, the

18:57

Parthenogenetic babies actually wind up

18:59

with less genetic variation

19:01

than their parents have. So

19:04

it makes them the most inbred thing that you can

19:06

think of in a vertebrate system. So

19:09

they're not like rigged. And that's why

19:11

Warren doesn't think it really makes sense to think of this

19:13

as a reproductive Hail Mary pass. Right?

19:16

Like, at least in the snakes that he's looked at, he

19:19

thinks these offspring are just too

19:21

inbred to meaningfully carry along the

19:23

torch to another generation. Instead, he

19:26

thinks that this ability to sort of randomly

19:28

occasionally make yourself reproduce, it's just

19:32

a vestigial thing that popped

19:34

into some ancient vertebrate ancestor

19:36

and has been passed

19:38

along from generation to generation.

19:42

My feeling is that these are very ancient

19:44

traits that are not detrimental. They're

19:46

not beneficial. But as

19:48

a result, they're just kind of meandering their way along

19:50

through lineage. They're not being lost because they don't kill

19:52

the female. Right? So

19:54

therefore, it's a trait that is just maintained. I ended

19:57

up taking this to Christine. And

20:00

she was very happy to agree that Warren

20:02

might be right. It could

20:04

be sort of an evolutionary artifact. But

20:07

she still doesn't think that Warren's

20:09

kind of weird snakes totally undermined

20:11

her hypothesis. Because she says,

20:13

sure, yes, most parthenogens produced this

20:16

way are flops, right? Like most

20:18

of these kinds of parthenogenetic embryos die.

20:20

There's something wrong with their genes, or

20:22

there's too much inbreeding, and they're gone.

20:26

Plenty of others don't make it to adulthood

20:28

for the same reason. But the whole

20:30

point of a Hail Mary pass is

20:32

that it's a long shot. It's

20:34

probably not going to make it, but it's

20:37

still better than not doing anything at all. You

20:40

miss 100% of the shots that

20:42

you don't take. That is right. If

20:44

you are a parthenote embryo, and

20:46

you're the one that actually makes

20:48

it through to adulthood, maybe

20:50

you just really won. Like you got

20:53

all the good genes, right? But

20:55

we don't know everything. There are

20:57

some extraordinary strategies out there

20:59

that we're yet to find.

21:02

I do think we're just really scraping the

21:04

top of this, I'm so bad

21:07

with metaphors. That's not the right one of it.

21:09

It's just the tip of the iceberg. There's

21:12

a lot more going on that we really

21:15

need to uncover. So

21:19

very possibly Warren is right.

21:21

And parthenogenesis is just a

21:23

weird little mistake in vertebrates. But

21:27

it's also possible that Christine's right.

21:29

And there's something interesting going

21:31

on here. I

21:33

think it's at least worth exploring. Because

21:36

after all, you do miss 100% of the shots

21:39

that you don't take. This

21:51

episode was reported and produced by me,

21:53

Bird Pinkerton. It was edited by Jorge

21:55

Just and Brian Resnick. Meredith Hadnott runs

21:57

the show. Noam Hasenfeld did. the

22:00

music, Christian Ayala did the mix and

22:02

the sound design, Melissa Hirsch

22:04

did our fact-checking, and the main

22:06

one is the fact that

22:08

house sparrows take dust baths. A

22:11

huge thank you to Alexis Sperling

22:13

and Fritz von Hollis, who took

22:15

a bunch of time to explain

22:17

Parthenogenesis to me. And

22:20

this podcast and all of Vox

22:22

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