- 1 week ago
The real story about “de-extinction”...
The Tasmanian tiger was declared extinct in 1982. But now… scientists are trying to bring it BACK.
And it’s not alone! You might’ve seen news about dire wolves, woolly mammoths, passenger pigeons… dodo birds… dinosaurs??
“De-extinction” has become a huge and urgent scientific debate. But when I took a deep dive into what’s really going on here, I realized we're getting this conversation very, very wrong.
We're on the cusp of a huge genetic breakthrough… and yet the most "huge if true" thing happening here isn’t bringing back extinct animals. It's what this means for all the animals alive today!
And very few people seem to know about it…
The Tasmanian tiger was declared extinct in 1982. But now… scientists are trying to bring it BACK.
And it’s not alone! You might’ve seen news about dire wolves, woolly mammoths, passenger pigeons… dodo birds… dinosaurs??
“De-extinction” has become a huge and urgent scientific debate. But when I took a deep dive into what’s really going on here, I realized we're getting this conversation very, very wrong.
We're on the cusp of a huge genetic breakthrough… and yet the most "huge if true" thing happening here isn’t bringing back extinct animals. It's what this means for all the animals alive today!
And very few people seem to know about it…
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LearningTranscript
00:00Look at this. This is rare footage from 1933.
00:03You see this dog-looking animal pacing back and forth in a cage?
00:06That's a Tasmanian tiger, one of the very last of its kind.
00:10It died in 1936, and the species was ultimately declared extinct.
00:14But now, scientists are trying to bring them back.
00:18And it's not alone.
00:19You might have seen headlines about dire wolves or woolly mammoths
00:22or dodo birds or passenger pigeons or dinosaurs.
00:25De-extinction has become a new and urgent scientific debate
00:30that we should all know about.
00:31But when I took a deep dive into what's really going on here,
00:34I realized that we're getting this conversation very, very wrong.
00:39Because we're on the cusp of a huge genetic breakthrough.
00:42But the most huge if true thing happening here
00:45isn't actually bringing back extinct animals.
00:48It's what this means for all the animals alive today.
00:51And very few people seem to know about it.
00:55De-extinction.
00:56De-extinction.
00:57Trying to bring back creatures from the past.
00:59We can do this.
00:59Resurrect the woolly mammoth.
01:01Dire wolf.
01:01Tasmanian tiger.
01:02It sounds like something out of a science fiction movie.
01:04It's no longer science fiction.
01:06That's the future.
01:13Alright, imagine you're a mad scientist,
01:16and you want to bring back an extinct animal.
01:18Here's the recipe.
01:19Step one, choose your animal.
01:21Like a mammoth.
01:22Now, from here, you need to choose one of three paths.
01:24And for each, you'll need different ingredients.
01:26You could try to take a close living relative of the animal that you chose
01:29and breed a bunch of them together until you get an animal with traits
01:33that roughly match the one that you wanted.
01:35This is the same basic process that made my dog Thor out of a wolf.
01:39But instead of trying to make something new and adorable,
01:41you're trying to make something old.
01:43It's called backbreeding, and it can work.
01:44Like with this guy.
01:45It's called a quagga.
01:46I actually have a little toy quagga right here.
01:50It's a subspecies of zebra native to South Africa.
01:52They have stripes on the head and neck, and the stripes fade away along the body.
01:56It was hunted to extinction by 1883.
01:59But we've already been able to bring a version of it back using backbreeding.
02:03This is a really exciting approach.
02:05And it can work for both animals and plants.
02:08But it is incredibly slow.
02:11It takes many generations of zebra to get there.
02:14And it's a guessing game.
02:15You don't know which genes will appear when and which will go away.
02:18In reality...
02:19It's a cool method that's been done, but probably pretty limited.
02:23Okay, but how about option two?
02:24I remember in Jurassic Park, they pulled dinosaur DNA from blood inside a fossilized mosquito.
02:31Bingo. Dino DNA.
02:34And then they cloned the animal based on that DNA.
02:37It's all part of the miracle of cloning.
02:38Cool. Let's do that.
02:40In real life, though, the ingredients that you need for this method aren't just the extinct animal's DNA.
02:44You need a whole living cell.
02:46Because cloning is actually a very specific scientific technique.
02:49The long name is somatic cell nuclear transfer.
02:53It means removing the nucleus out of an egg cell and replacing it with the nucleus of a body or
02:58somatic cell of the animal you want to clone.
03:01And then you put that egg with its new nucleus into an animal where it can grow.
03:05And this actually works.
03:08Almost.
03:09People tried this in the early 2000s with an extinct species called the Bucardo.
03:15These animals are so cool.
03:17But by 2000, there was only one Bucardo left.
03:20But luckily, this was four years after Dolly the sheep was famously successfully cloned.
03:25So in an attempt to save the species, some quick thinking biologists put tissue samples from the remaining Bucardo in
03:31storage.
03:31And then they were able to take the nucleus from those cells and put them into the cells of domestic
03:35goat hybrids.
03:36And in 2003, a baby Bucardo was born.
03:40Unfortunately, their first clone that was born had a malformed lung and didn't survive.
03:46This hasn't been tried again.
03:48So we are able to clone animals when we have living cells, which is wild.
03:54But unlike the Bucardo, nobody carefully preserved the whole cells of a mammoth.
03:58The biggest challenge is needing those living cells in the first place.
04:01Because it turns out that cells have a shelf life.
04:04Once an animal dies, their cells are typically pretty short-lived, dying off within hours or days.
04:09But freezing can dramatically slow this process.
04:13Which is why there's been hope that animals found preserved in ice, like this 40,000-year-old baby mammoth,
04:19might have some usable cells.
04:21But so far, no revivable cells have been found.
04:24So cloning is hard.
04:26But we've got one more option.
04:28And this one is by far the most popular.
04:30For the 99.99% of extinct species, we have to use the third method, gene editing.
04:37If you imagine DNA as a group of blocks, each block here could represent a gene.
04:42Like this one tells me the shape of the skull.
04:44And this one tells me ear size.
04:45And maybe this one tells me thick woolly coat.
04:48And then stacked together, they give me the instructions for how to build this specific animal.
04:51The challenge is, like living cells have a shelf life, so does DNA.
04:56Once an animal dies, the DNA in its cells starts to break down into tinier and tinier and tinier fragments
05:02until eventually there's nothing left.
05:04That's why right now we can't bring back animals that went extinct too long ago, like the dinosaurs.
05:09Too much time has passed and their DNA is way too fragmented.
05:12But if we use an animal that died off fairly recently, or was frozen in just the right way,
05:16scientists can figure out what some of those key missing pieces are.
05:19And replicate this stack of blocks in another animal.
05:23This is gene editing.
05:24You compare the stack of DNA blocks of the extinct animal with the blocks of a close living relative to
05:29see where the two are different,
05:31and edit the DNA in the living relative so it resembles the DNA in the extinct one.
05:36This is what they're trying to do with woolly mammoths.
05:39And dire wolves.
05:41But they won't be exactly like the extinct animal.
05:44In fact, people online were really quick to point out that these actually aren't really dire wolves at all.
05:50It's better to think of them as genetically modified grey wolves.
05:54But the thing is, that was intentional.
05:56Scientists are choosing which exact traits to manipulate to get the outcomes that they want.
06:00And they want to do it by making the least amount of edits possible.
06:03I asked the scientist in charge of the dire wolf project why.
06:06I'm thinking about de-extinction, and I'm also thinking about animal welfare.
06:10Every time we change the sequence of DNA in a genetic background, there's a risk that something happens that we
06:16didn't predict.
06:17I want healthy animals in the end.
06:19Therefore, my goal is the fewest number of changes necessary to de-extinct those important characteristics.
06:25So, de-extinction might have a branding problem.
06:29Because people on one side are looking at the literal definition and saying,
06:32that's not de-extinction.
06:33And they're right, that's not the exact animal.
06:36But then on the other side of this, you have scientists who are saying,
06:39bringing back exact replicas isn't really the point.
06:42They're not trying to de-extinct the exact animal.
06:46They're trying to de-extinct what the animal did.
06:50In the end, the whole dire wolf or not dire wolf debate doesn't really matter.
06:54Branding them this way makes for a good headline, but it's not technically accurate.
06:59And while the effort to bring back a version of a dire wolf or a woolly mammoth is totally cool,
07:04I think it's a distraction from what is the real, huge if true, use of this technology.
07:11But first, let me show you something.
07:12This new phone case is special.
07:14It's not just that it's built with insane impact resistance and durability,
07:18or that it has a lifetime warranty against yellowing.
07:21Those things are important.
07:22But what's even more important is their mission to tackle plastic waste.
07:25Every year, 19 to 23 million tons of plastic waste leaks into lakes and rivers and oceans.
07:33First, they plan to become plastic neutral.
07:35So they built a closed loop model.
07:37The phone cases are 100% recyclable.
07:39You can send back your old phone case, and they break it down and repurpose it into a brand new
07:43one,
07:44giving it a second or third or more life.
07:46It's even got a QR code on the inside so you can track the product's life cycle.
07:50But what they really wanted was to tackle all plastic waste.
07:53Not just modern plastic, but also legacy and future plastic, too.
07:57What if you could take plastic waste out of the ocean and then use or upcycle it?
08:03That's exactly what they do.
08:05They've built a solar-powered floating platform that uses water jets to create pressure differences that guide floating garbage into
08:12its collection area.
08:13It's like a robot vacuum for ocean cleanup.
08:15This is new.
08:16They're testing it right now.
08:17But it's the kind of effort that I find really optimistic.
08:21Protecting your phone and protecting oceans, too.
08:23If you want to check it out, use the code CLIO for 10% off at the link in my
08:27description.
08:28There have been five times in the history of Earth where over 75% of all life was lost.
08:33And many scientists say we're going through a sixth right now.
08:36And while prior mass extinctions were caused by natural disasters, this one seems to be caused by us.
08:41But hang on, even if you don't care about animals and biodiversity, this sucks for us.
08:46This has huge impacts on our food and our homes and everything we rely on to survive.
08:51And here's the optimistic part.
08:52The same tools that we've been talking about to bring back extinct animals can also be used to help animals
08:57not go extinct in the first place.
09:00This is the part that got me most excited.
09:02And this is what I don't see enough people talking about.
09:04It's called genetic rescue.
09:06Meet the black-footed ferret.
09:07This adorable little guy is in need of genetic rescue because...
09:11Every living black-footed ferret alive today are first cousins.
09:15Yikes.
09:17This little guy nearly went extinct in 1979.
09:20Because of humans, the population crashed.
09:22But fortunately, they've started to come back.
09:24The problem now is that this new group of black-footed ferrets...
09:28It has really, really low diversity.
09:30Very small gene pool.
09:31Scientists call this the bottleneck effect.
09:34If your group doesn't have enough genetic variety, you're vulnerable to things like disease and weird genetic mutations.
09:39This is a problem facing dozens of species whose populations put them at risk for genetic bottlenecking.
09:46But today, scientists are exploring gene editing to create more genetic diversity in some of those groups.
09:52We can take DNA from a museum stuffed animal from 100 years ago, sequence its DNA, and then edit it
09:59into living black-footed ferrets.
10:01That's one way to get diversity back, which we are working on.
10:05Another great example of using minimal gene editing to save a species is this little guy.
10:10The northern quoll from Australia.
10:12Look how cute he is!
10:14But they're expected to be extinct in the wild within the next 10 years.
10:17Because of this guy.
10:18This toad.
10:19This is the cane toad.
10:21And it's an invasive species.
10:22It's got a deadly toxin on its skin.
10:24So what happens is...
10:25So our carnivorous little quoll will eat the cane toad and they die instantly from that toxin.
10:31But scientists found that it's just one single letter of genetic code that makes them either die from eating a
10:37cane toad or completely resistant.
10:39Just one letter.
10:41So they're working on a way to introduce that one change into the population and make quolls that are able
10:46to eat cane toads without dying.
10:48Saving an entire species.
10:50In theory, you could do a lot of this.
10:52Not just making key animals poison resistant, but also disease resistant or heat resistant.
10:57There are projects to do this on coral reefs.
10:59Huge if true.
11:01But then...
11:02Why are we trying to de-extinct animals at all?
11:05That brings us back to the Tasmanian tiger.
11:08Humans hunted these tigers until there were none left in the wild.
11:11But they didn't understand what would happen next.
11:13Without the tiger, Tasmania lost its only apex predator.
11:16A keystone species, meaning it has a huge impact on its ecosystem.
11:19And without them...
11:21There's been an explosion of wallabies and kangaroos there.
11:24They're eating all the shrubs.
11:26They're eating all the bushes.
11:27You know, that's impacting the bird populations.
11:29It's changing the landscape.
11:31Which means that now other species are at risk.
11:33Like the Tasmanian devil.
11:34They developed this incredibly strange disease.
11:37And it's actually like a cancer tumor that grows on their face.
11:40And they spread it from animal to animal.
11:42Apex predators used to reduce diseases like this by eating sick members of the population.
11:47By killing all the Tasmanian tigers, we created a butterfly effect that's rippling through the food chain to this day.
11:53So, some are proposing...
11:55The only way we'll ever be able to bring that ecosystem back into balance is to put the Tasmanian tiger
12:00back into it.
12:01Tasmania is an island cut off from other natural predators.
12:04And many scientists agree that there's no other living species that could replace what the thylacine could do here.
12:10But could we actually do this?
12:12Well, they're following the recipe.
12:14They've identified the animal.
12:15They've sequenced the DNA.
12:17As for close relatives, this is the closest living animal to the thylacine.
12:20Their genetic makeup is 99.9% identical.
12:24And then you just edit that 0.1% where they're different.
12:28And that will turn that then into a Tasmanian tiger or a thylacine cell.
12:33Wait, 0.1%?
12:34That's actually a lot genetically.
12:36And that's the bit that's going to take a really, really long time to get that bit done.
12:41At this point, though, you might be wondering, whoa, whoa, whoa, whoa, whoa.
12:44Did we not learn our lesson from Jurassic Park?
12:47What are the consequences of actually doing this?
12:50When is it okay to use this technology and when is it not?
12:54In other words, how do we get this right?
12:56What happens when you drop a predator back into an environment that hasn't seen it in decades?
13:01Well, in this case, it seems like a lot of the animals remember them.
13:06We made some replica thylacines and we took them out into the bush in Tasmania.
13:11We saw that they absolutely, without doubt, even though it's been over 100 years since they were really there,
13:17all of those animals remember the thylacine.
13:20If there's a fox or a goat, they don't really care.
13:22But if they see the thylacine, they are out of there.
13:25But what about the thylacine's instincts?
13:27How would it know to behave right, like a predator?
13:30How much of an animal is nature versus nurture?
13:32There's real debate here.
13:34I frankly don't think that it will ever happen that we will see thylacines into the wild.
13:39But advocates for the thylacine would argue.
13:40Those behaviours are really hardwired in any animal's brain.
13:45The best example of this would be domestic cats.
13:47These are a pounce predator animal that have been living in our houses now for hundreds of generations,
13:53eating tinned cat food or little crispy biscuits.
13:56But if you wiggle a feather in front of them or a mouse runs across the floor,
14:00they immediately know that they are a pounce predator and they will pounce and kill and eat that animal.
14:06We don't really know until we try. And they're trying.
14:09This is all hard, but it's not like we're creating things that are suddenly going to just be released into
14:14the wild.
14:15You would have them in a very large enclosure.
14:17You would really study them very very closely and make sure that they have taken on all of the behaviours
14:23so that by the time we get a population that we could think about releasing into the wild,
14:27we know that they're going to be able to really thrive once again.
14:30What this all means, best case, is we're still decades away from a wild Tasmanian tiger.
14:36But this technology is coming.
14:37And we need to be part of that conversation right now.
14:40It's obviously fun to imagine Jurassic Park or bringing back a dire wolf.
14:45But as we have this conversation, we gotta be careful.
14:48We're talking about manipulating billions of years of evolution.
14:51There are huge stakes.
14:53Ethical stakes about using animals as lab experiments.
14:56Environmental stakes that could accidentally devastate entire ecosystems.
14:59And, of course, the stakes of not doing absolutely everything we can.
15:05To me personally, the most huge if true optimistic bit of all of this
15:10isn't actually bringing back animals from the past.
15:13It's using all of this incredible science and technology
15:16to help keep the animals and the world that we live in now healthy.
15:21I would love people to go away from this and be like,
15:23de-extinction science is conservation science and we absolutely have to use it.
15:28We are living in a world that we changed before we understood the consequences.
15:32The real debate about de-extinction isn't what's a dire wolf.
15:36It's what responsibility do we have to the world we created?
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