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brought civilization, God, and empire.
Exploring the history, extinction, and potential cloning of the Tasmanian tiger through recovered DNA and scientific challenges.
Key Takeaways
- The thylacine was wrongly blamed for sheep losses, leading to its extinction.
- Some DNA from preserved thylacines has survived, enabling potential cloning efforts.
- Cloning an extinct species presents major scientific and technical challenges.
- Convergent evolution caused thylacines to resemble dogs despite different ancestry.
- De-extinction could redefine our understanding of extinction and conservation.
Summary
- The video discusses the arrival of European settlers in Australia and their impact on native species, including the thylacine.
- Thylacines were misunderstood and scapegoated as sheep killers, leading to their extermination by settlers.
- The last known thylacine died in captivity in 1936 at the Hobart Zoo, marking a symbolic extinction date.
- Despite breeding in captivity, lack of political and social will prevented conservation efforts in the early 20th century.
- Recent discoveries show some thylacine DNA has survived in museum specimens preserved in alcohol for over 140 years.
- Scientists face significant challenges with fragmented and degraded DNA in efforts to clone the extinct species.
- The cloning process involves inserting extinct animal DNA into a living host egg cell, but reconstructing the full genome is complex.
- The video highlights the biological phenomenon of convergent evolution between thylacines and dogs despite distant relations.
- Scientists express hope that advances in DNA technology could lead to de-extinction, questioning if extinction is truly permanent.
- The video features key scientists involved in the DNA recovery and cloning research, emphasizing the pioneering nature of the work.
Full Transcript — Download SRT & Markdown
Speaker A
Which meant English-style villages, churches, even grand country mansions.
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They also brought their sheep, and here in their new Southern Hemisphere home, they prospered and got rich on wool.
Speaker B
They couldn't adapt to Australia, Australia had to be adapted to them.
Speaker B
The creatures were weird, they didn't understand them, so they wanted to make it into a kind of a little England.
Speaker B
So they got rid of all the native trees, they got rid of all the native flowers, and with them, unfortunately, went the thylacine.
Speaker A
Right from the start, the thylacine confused them; they couldn't get used to the fact that they were not looking at a dog.
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And then there were those stripes, which made it look, if anything, like a big cat.
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You can see the confusion in their art.
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Some drew a noble wolf, others a cringing mongrel.
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And when cameras arrived, it only added to the confusion.
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All these photos are of captive thylacines, in some cases, whole families of them.
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Not only did they look like dogs, but they seemed to behave like them, though some obviously acquired a taste for chickens.
Speaker A
But one of the more interesting photos to come to light recently does portray them as marsupials.
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Here's a family of stuffed thylacines in dog-like pose, except there's a little one sticking out of its mother's pouch.
Speaker B
One of the most incredible things about the thylacine is its convergence.
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It is probably the best example in the world of the biological phenomenon where one animal comes to look identical to another because they do the same sorts of things.
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The ancestors of dogs are related to bears; they have nothing to do with anything in Australia.
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The ancestors of thylacines are related to kangaroos and wombats.
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And yet these two animals, doing the same basic kinds of things, they have come to look identical to each other.
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So identical, internally in their skeleton, in their skull, in their external features, that it's not uncommon for a biologist to mistake one for the other.
Speaker A
But something was killing the settlers' sheep; for millions of years, thylacines had hunted wallabies and other small animals.
Speaker A
Now, a myth grew up that it was a sheep killer.
Speaker A
Yet, whilst feral dogs ran loose in the countryside, the thylacine got the blame.
Speaker A
It seems that the settlers demanded a scapegoat, so a price was put on its head; what had taken nature some 50 million years to evolve was exterminated in only 50.
Speaker C
In many respects, the destruction of the thylacine was simply a criminal act of the worst kind, a criminal act in terms of the animal was scapegoated and destroyed in Tasmania for the mythical belief that it attacked sheep when there is very little evidence to suggest that it did so.
Speaker B
This is the tragedy of this situation; it was not the thylacines that were eating the sheep, that was so rare it didn't even matter.
Speaker B
What was actually happening was wild dogs were eating those sheep.
Speaker D
This area here, while nothing remains today, was one of two areas at the zoo where the Tasmanian tigers were housed.
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Extinction finally arrived on the 7th of September, 1936.
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The date was symbolic.
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An extinction that you could actually put a time and a place to.
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Here at the site of the old Hobart Zoo, they still commemorate the day when the last thylacine died.
Speaker D
The last thylacine in the zoo, uh, which had been here for 12 years,
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seven months,
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died.
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In effect, they became extinct.
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So this is the last site of the thylacine.
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As far as we know it.
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There isn't even a memorial to the last thylacine.
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Not a stone of its enclosure remains.
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And when it died, its passing was considered of such little consequence that its body was sent to the garbage dump.
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This was taken in the Hobart Zoo and could possibly be our last look at the thylacine.
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Amazingly, some thylacines had hung on until the motion picture age.
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This film shows one pathetically pacing around its cage in the Hobart Zoo.
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Other films shows a more animated animal, presumably near feeding time.
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And there's that gigantic yawn, for its size, one of the widest gapes of any mammal.
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And there were thylacines in other zoos around the world.
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This image was recently discovered.
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It's of a thylacine in the London Zoo, filmed back in 1930.
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You're seeing it now for the first time on television.
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The particular tragedy here, of course, is that the species could have been saved.
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Scientists had the knowledge.
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It had bred in captivity.
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But the political will and the social will to change society's values, the desire even to save the species itself was missing from the lives of scientists in the early 20th century.
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But hopefully, the 21st century scientists will make amends.
Speaker E
Looks like there might be a little bit of DNA.
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Yeah, something seems to be clustering.
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Back in the Australian Museum, Mike Archer's moment of truth had arrived.
Speaker E
Oh, my God.
Speaker A
The first bits of a miracle are in your hand.
Speaker E
It seems to be just a tiny amount of um, sort of cotton wool.
Speaker A
Oh, yeah.
Speaker E
Or down there.
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Very small.
Speaker E
Fantastic.
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Small.
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Their fears were unfounded.
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After 140 years in alcohol, some DNA had survived.
Speaker A
That's great.
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Now, that couldn't be anything other than basically DNA.
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That's um, that's been indicated.
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What's the significance of that?
Speaker B
Uh, my heart is beating really fast.
Speaker B
I mean, we have dreamed about this thing for years, I've thought about it, you know, at least 20 years ago.
Speaker B
And I never really thought we'd get to this point.
Speaker B
I mean, it was, it was impossible, told by many people to us, we'd never get here.
Speaker B
Uh, the dream is starting to become a reality.
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I mean, we're not there yet.
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But step one, the fantastic step of actually getting DNA, um, is occurring.
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So I could not be a happier man than any in the whole world.
Speaker B
We are really going here.
Speaker E
That's great.
Speaker E
That's fantastic.
Speaker A
It was Mike Archer's Eureka moment, a moment he intended to share with the world.
Speaker B
Ladies and gentlemen, we are here to announce what is probably the biological equivalent of human beings taking their first step on the moon.
Speaker B
Nobody's ever done what we have just done.
Speaker B
It is the threshold of what will be a very exciting series of opportunities to maybe question whether extinction really is forever.
Speaker A
But despite the extravagant claims, science was still a long way short of cloning a thylacine.
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As Mike Archer knew only too well.
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The DNA was seriously fragmented.
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How do we put it together?
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As chromosomes.
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How do we know how many chromosomes we should have?
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How do we get the DNA viable?
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It's pickled.
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How do we get it to start to be in a format where it can actually start to code for and produce proteins?
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So many challenges.
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When most of us think of cloning, we think of Dolly.
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The first mammal cloned from an adult cell.
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Since then, scientists have also cloned cattle, mice,
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even human embryos.
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Put simply, cloning works like this.
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Pick a cell from an animal, remove its genetic material, put it into the egg of a host animal that's had its own genetic material removed.
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Zap it with an electrical charge.
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And it's fused.
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If you're successful, the cells divide and you've got a cloned embryo.
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But what is nature's recipe for a mouse, or a sheep, or a pig?
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In most cases, scientists simply don't know.
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And they don't have to.
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All they're doing is manipulating nature's code.
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But reconstructing that code is a very different story.
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What we've got to do is something extraordinarily challenging.
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We've got to take dead DNA from an extinct animal and insert that into the cell of a living animal.
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And keep our fingers crossed that what we're going to get is the result of this process.
Speaker B
Is the extinct animal back alive again?
Speaker A
The job of trying to sort out all this DNA falls to Doctors Karen Firestone and Don Colgan.
Speaker F
We've got the control.
Speaker F
Oh, it is interesting.
Speaker F
I guess it's that heart doesn't seem to have much better condition DNA than the liver.
Speaker A
It's hard to know really where to begin.
Speaker A
Particularly when it's so fragmented, and there's always a nagging feeling that it could be contaminated.
Speaker F
It's ancient DNA, it's um, degraded.
Speaker F
It's broken down into fairly small fragments.
Speaker G
We're looking at um, two to three million different pieces that we have to put in their correct order.
Speaker F
It's also in very low copy number, um, and it's, it's a difficult material to work with.
Speaker A
Like Jurassic Park, they must rebuild an extinct animal.
Speaker A
This is the stuff of science fiction.
Speaker H
Well, I think he's in fairyland.
Speaker I
It might as well be called cloning ice.
Speaker I
I think, um, it's so much of a gimmick.
Speaker H
Getting one gene out is difficult enough.
Speaker H
Getting out a whole genome, I think, is almost impossible.
Speaker I
The bottom line, dollars, dollars.
Speaker I
They would be worth probably tens of millions of dollars, and who on earth is going to put a $10 million thylacine that doesn't know how to hunt, got no survival skills,
Speaker I
um, a compromised immune system and aging rapidly out there?
Speaker I
It's just not going to happen.
Speaker H
Thylacines, there was one thylacine.
Speaker H
And this thylacine is a gone thylacine.
Speaker H
And no amount of wishing and really good science will ever bring the thylacine back.
Speaker H
It's gone.
Speaker A
But not everyone is so negative.
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In a small Massachusetts country town, lives one of the world's leading genetic scientists.
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If anyone should be known as Dr. Clone, it's Robert Lanza.
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He's a man who combines an aptitude for cutting-edge science with a passion for stones and bones.
Speaker J
This is a Brontosaurus femur.
Speaker J
This is a creature that was some 50 tons.
Speaker J
It was probably the size of this entire house.
Speaker J
And you can actually see where this creature at some point was actually attacked, perhaps by a T-Rex.
Speaker J
You can see where the actual skin of the bone was ripped, and it actually formed a callus over the damaged part of the bone.
Speaker J
And here what we have is a crinoid.
Speaker J
This is a pretty interesting creature.
Speaker A
His house is a monument to extinction.
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Prehistoric sea creatures, animals, ancient plants, even dinosaur footprints.
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All are displayed like artworks around his house.
Speaker J
And it was almost like it happened yesterday.
Speaker J
I mean, you can see the smudge marks.
Speaker J
And over here what you have is a nest of dinosaur eggs that's about 100 million years old.
Speaker A
Bob Lanza has created his own private Jurassic Park.
Speaker J
And you can actually see the shells where the the shells actually started to break off from the egg.
Speaker A
But he's also taken a cautious interest in cloning the thylacine.
Speaker J
I think it's definitely a feasible project in the next decade or so.
Speaker J
We have a number of the technologies already working at this point.
Speaker J
For instance, we know with the human genome project, for instance, we know that just a few years ago, people thought that that was going to be many, many years in the future.
Speaker J
And already we've already succeeded there.
Speaker J
So that's a good example of how fast our science is evolving.
Speaker A
Just over a year ago, he and his team confounded their critics when they cloned the world's first endangered species.
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A rare Asian ox called a gaur.
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It was the first time the DNA of one species had been put into the egg of another.
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The cow's mother was a domestic cow.
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Unfortunately, the gaur died after two days from a common infection.
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But the point had been made, a cross-species clone had been born.
Speaker J
I was told that we couldn't use the cross-species cloning to clone the first endangered species.
Speaker J
I was told by virtually every scientist that that was an impossibility.
Speaker J
And in fact, no one had ever even gotten a pregnancy at that point.
Speaker J
And we ended up with a beautiful little baby gaur.
Speaker J
So to those skeptics, I say, you know, we did it there.
Speaker J
We did it a few years ago when the first animal was actually cloned from an adult cell.
Speaker J
And so I think that that is more the norm.
Speaker J
I think that the scientific community is very conservative.
Speaker J
And rightly so.
Speaker J
I think there's no question, this is an ambitious project.
Speaker J
And it's going to take many years to have success.
Topics:Tasmanian tigerthylacineextinctioncloningde-extinctionDNA recoveryconvergent evolutionHobart Zoowildlife conservationgenetic research
