We often talk about saving endangered species from extinction, but what if I told you that extinction doesn't have to be forever, Matthew?

I'd call you a filthy liar.

Well, things that we've long considered gone forever have a habit of reappearing from time to time.

So every once in a while, kids, children, are born with tails.

And that is an ancestral characteristic.

CRAIG: This is Jack Horner, curator of paleontology at the Museum of the Rockies in Bozeman, Montana.

He's widely known for discovering evidence of parental care in dinosaurs, and was also the inspiration for the character of Dr. Alan Grant in "Jurassic Park."

JACK HORNER: Every once in a while, snakes are born with legs.

That is an ancestral gene that accidentally comes on.

I'm trying to find those atavistic genes to intentionally make them come on.

Hold on.

I thought he was a paleontologist.

Shouldn't he be digging up dinosaur bones and frightening obnoxious children?

You are alive when they start to eat you.

Why is he looking for snakes with legs and babies with tails?

Well, he also has this project-- Where I am attempting to retro-engineer a bird back to something that looks a little more like an extinct dinosaur.

CRAIG: Dinosaurs have been extinct for 65 million years.

And although we've seen them brought back to life many times in stories and movies, no one has ever seen a real live dinosaur.

But that all might change if Jack Horner has his way.

Humans have been modifying animals for a long time.

We breed various kinds of dogs and cats and cows and pigs and whatever, you know.

And we change the way they look.

And people always say, well, why would you make a dino-chicken?

And I always say, why did somebody want a chihuahua?

I mean, you had to start with a wolf to get a chihuahua.

And I'd say it's for the same reason, I guess.

Somebody wanted a chihuahua to have a little dog, right, that they could carry around with them, I guess.

And I would like a pet dinosaur.

So that's for your own-- you'd just like to have a pet.

MATTHEW: OK.

He wants a pet dinosaur, which would be awesome, obviously.

But is it even possible to bring back dinosaurs?

So you start with a bird embryo and you switch a gene on that has been turned off.

Birds already share a lot of characteristics with dinosaurs.

In fact-- Birds share more characteristics with extinct dinosaurs than with any other group of animal.

[t-rex roar] [rooster crowing] Birds' closest living relatives are crocodiles and alligators.

MATTHEW: They don't seem to have much in common, do they?

CRAIG: But if dinosaurs were alive today, you might have trouble telling some of them apart from their bird cousins.

Both have three toed feet, hollow bones, hard shell eggs, and feathers.

There's just a long list of characteristics.

Remember when I said no one had seen a living dinosaur?

Well, that's not exactly true.

Birds are dinosaurs.

We see dinosaurs every day.

So Horner wouldn't exactly be bringing back the dinosaur.

He'd be making a bird with characteristics of its ancient ancestors.

JACK HORNER: That's our hypothesis.

We hypothesize or theorize that birds are actually a group of dinosaurs.

CRAIG: But it's not the traits they share that Jack Horner is interested in.

He wants to turn on the traits the birds lost, like the snout, teeth, tail, and clawed hands.

JACK HORNER: Really, we're looking at those four features.

And two of the four features we now can reverse.

A team of scientists from Yale and Harvard universities were able to successfully create a chicken with a dinosaur-like snout by turning off the genes that code for the beak.

Researchers have also observed bird embryos with a mutation that allows for the growth of alligator-like teeth.

But none of these animals have ever survived to hatch.

By just going in and turning ancestral genes back on again, we can produce a bird that actually has a snout like its ancestor.

And eventually, all the rest of those traits.

But they're not really lost, right?

They're still in the bird genome, just turned off.

Yes.

Just because living things don't exhibit those features anymore, like claws or teeth, it doesn't mean that the gene that coded for them goes away.

In fact, once the trait disappears, it's no longer subject to natural selection.

Therefore, there's no pressure for the gene to do anything at all.

Evolution just leaves it alone.

However, given enough time, some of those dormant genes will eventually be lost through the process of random mutation.

JACK HORNER: We do lose genes occasionally.

And in fact, birds have lost the enamel gene.

So even though we can put teeth back into a bird by flipping a switch, the enamel gene is gone.

They've lost it.

And so if we are going to give them hard teeth, the enamel teeth, we are going to have to do it transgenically which means taking the enamel gene out of a different animal and putting it into a bird, which is something we can do as well.

I mean, we do transgenic engineering already.

CRAIG: The process of inserting new genes into an organism to make new characteristics is called transgenesis.

Many transgenic animals already exist.

By taking the genes that allow a jellyfish to glow under black light, scientists at the University of Hawaii, in partnership with two universities in Turkey, successfully made glow in the dark rabbits.

Although the bunnies look white under normal conditions, put under a black light, they glow bright green, thanks to the jellyfish genes.

And bunnies aren't the only animal scientists have done this to.

Mice, goats, cows, pigs, and chickens have all been made to glow in the dark.

JACK HORNER: Once we understand what genes do and how to turn them on and turn them off, we certainly could design any kind of animal we wanted.

Even before we make a dino-chicken, if we wanted to, we could probably make a unicorn pretty easily.

And we could make a glow in the dark unicorn because we could do it transgenically.

Wow.

In fact, we could probably make a pink glow in the dark unicorn.

CRAIG: What will come first?

The dinosaur chicken or the dinosaur chicken egg?

The dinosaur chicken egg.

That's for sure?

Mm hmm.

OK.

The egg is always first.

Evolution is about modifications in an organism over time.

There are no bigger jumps in evolution than that which happens between a parent and its offspring.

You are never a different species than your parent.

But you are a mutant compared to your parent because you are different.

You're not a clone.

And so the egg is where that mutation occurs.

So whatever changes has ever occurred is in the egg first.

All right.

Well, thanks for that.

That make sense?

CRAIG: Yeah.

Thanks for solving the age old mystery.

Right.

MATTHEW: OK. Let's say someone makes a dino-chicken.

What would they do with it?

Put it in a theme park?

Set it free in the wild?

Dinosaurs haven't been around for millions of years, and the earth has changed a lot.

Could dinosaurs even survive today?

Of course.

CRAIG: Yeah?

Oh, yeah.

I mean, it's still a chicken.

So it would be mainly, the behavior of it will still just be a chicken?

It'll still be a chicken.

We're not changing their DNA.

We're switching genes on and switching genes off in one animal at a time.

So you can't even breed them.

I mean, if you breed a dino-chicken with a chicken, you have a chicken.

All right.

And so someday I know we'll be able to change the DNA and change animals completely.

But that's not the dino-chicken project.

That's not what we're doing.

MATTHEW: Dinosaurs are cool and all, but aren't there other scientific projects more worthy of support?

Like what would be the purpose of a dino-chicken?

It could be used to test out one of the most controversial scientific theories ever put forth.

A lot of people-- what is it, 43% of the population-- don't believe in evolution, for example.

And you can't retro-engineer an animal back to anything if evolution doesn't work.

But if it does work, you can.

And so it's sort of a ground proof of evolution.

I mean, you can't bring back ancestral characters if there are no ancestors.

So it's a great way to teach about evolution.

It's also just a cool way to study a very complex kind of science, genetics.

And it's also just, in the end, we'll have a cool animal.

Yeah.

I like that attitude.

MATTHEW: OK.

I understand the scientific merit to it and I know it'd be freaking awesome.

But isn't it kind of reckless and possibly unethical to tamper with the genes of an unborn chicken and make some kind of mutant hybrid?

Is it wrong to try and control nature like that?

JACK HORNER: Humans occupy so much of the world that we basically control every animal on earth right now.

I mean, we control the ecosystems of every single thing alive today.

And the animals that have adapted to live with us, we don't like.

They're the weed species, right?

If they can live in our backyard, we don't like them-- CRAIG: A squirrel, yeah.

JACK HORNER: --because they're eating something.

The pretty animals, we're all concerned about.

And the pretty animals are going extinct because there's too much of us.

The animals that we do best with are the ones we've domesticated, the ones we've created.

The ones we have genetically created are the ones that we like the most.

And so the dino-chicken is just another version of a domesticated animal.

CRAIG: A really cool one.

A really cool one, I think.

Yeah.

Well, thank you very much.

You're welcome.

So what do you think?

Will the dino-chicken be like any other domesticated animal we breed?

Or is it an abomination of nature, a horrifying example of scientific hubris destined to end in terrible bloodshed?

Let us know in the comments.

Wow, Matt.

Thanks for watching.

If you want to help support the show, go to Patreon.com and become a supporter, or you can join our digital street team and help us promote the show.

Last week, we went to Olney, Illinois, and checked out the squirrels there.

And this is what you had to say about it.

Kabtastick pointed out that it's probably not correct to say recessive gene and we should have said recessive allele.

And that's probably true.

Alleles are the variation of a gene that determines a specific trait like albinism.

So a gene for pigment could have multiple alleles that are dominant and recessive.

But for simplicity's sake, we just called it a recessive gene.

Paul St. Aldan was confused how the population of albino squirrels became so large if they came from such few squirrels and the gene was recessive.

Well, the answer is we don't really know.

A law disallowing dogs from running at large was first enacted in 1925 and the albino squirrel population reached its peak in the 1940s.

So maybe the law had something to do with it?

People were probably always looking out for the albino squirrels, feeding them, and things like that.

So that probably helped.

But I mean, over the years, more laws were enacted and people have been caring for those squirrels since then.

And the population is dwindling now.

So who knows?

We saw several comments where people seemed to think that the people that only were breeding the albino squirrels-- they weren't breeding them.

They just take care of the squirrels when they got hurt.

That's what Belinda was doing.

She was rehabilitating them.

And they feed them and things like that.

So there's no breeding going on.

And when she takes care of them, she takes care of both the albino squirrels and the gray squirrels.

So it's all equal.

There's no discrimination happening in Olney.

Thanks for your comments.

Next week, we're going to watch Craig try to start a fire the old-fashioned way.

Can he do it?

I don't know.

Probably not.

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