Robyn Williams: And still at the University of New South Wales, meet once more Mike Archer, who himself has won the award of favourite lecturer from many of his students. And in 2019 he also won the Society of Vertebrate Palaeontologists' highest award, the Romer-Simpson Medal. A global recognition. Here he is in Hobart in a talk about resurrection and the way science can bring the creatures back.

Mike Archer: Thank you very much. Yes, it's an interesting thing that the Academy said to me would I come and talk about this topic. And I think back on the years when I was actually inducted into the Academy of Science, that was one of the biggest honours of my life. And the people who were urging me to come in and supporting this initiative said to me, you know, you've got to give an introductory speech when you come into the Academy. And I said, yeah? And they said but there's one thing we want to warn you about, don't say anything about trying to bring back extinct animals into the world again. And here I am, asked by the Academy to come and talk about this topic. So I think this is a wonderful circle of life that is coming back here.

Okay, I do want to ask this question; does extinction have to be forever? There are massive problems in this area, the idea of trying to bring back animals that have gone extinct. It's not a simple process. But I think it's one of these processes that I'm discovering, much to my surprise, how many people around the world are interested in trying to do this. They are people of the same kind who decided that they were tired of whacking stones together in caves and decided to try something new, and they are less reluctant to listen to people telling them what they can't do, so they thought let's just give it a try. And there are people all over the world trying this.

And so I got involved in this for two projects in particular. One was the Thylacine Project, and of course this is very dear to the hearts of Tasmanians. Do we have to have the thylacine extinct forever? And the other one, which I started later, was the gastric brooding frog. I started on the Thylacine Project specifically when I was in the Australian Museum as the director there. See, I got sick of waiting to have somebody have a look at whether or not this was possible. And we made progress. But when I left, the guy who replaced me, the director…it's like what happens when the next lion comes into the pride, you know, all the young of the previous lion get killed off, and my project, the Thylacine Project which I started in the Australian Museum, just got immediately dropped in the bin and they didn't pursue it. So that's why I started the gastric brooding frog.

There's a whole range of people who could be acknowledged here and I've had massive help and, I'd have to say, that enabling us to get on with the Lazarus Project focused on the gastric brooding frog, I was helped by Dick Smith and Gary Johnson. These two people were not investing particularly in conservation projects but they were very interested in the possibility of the technology that could be involved in bringing back extinct animals. And so they made this possible. And also John Shine, the president of the Academy of Science also supported this work straight up.

Okay, the Thylacine Project, if you've seen the TED Talk that I've got out there, I have said that I think that of all the animals we might focus on, to think about bringing them back, we should focus in particular on the ones that we've had some responsibility for exterminating, and I have said I think we have a moral responsibility. If technology brings us to the point where we could think about bringing these back, I think those are the animals in particular that we should feel a kind of moral imperative to at least consider whether we can undo the terrible things we did in obliterating the species in the first place.

Okay, first this Lazarus Project. This is focused on this extraordinarily weird frog. How many people here have heard of the gastric brooding frog? Okay, about half of you. It's a fascinating frog, and it's probably one of the things that makes Australia famous, certainly among amphibian biologists around the world. What happened was a biologist, David Liem actually, found this thing in one of the rivers in south-east Queensland. He knew it was weird because it had webbed feet. It seemed to be an aquatic frog. It was like the birdo people talk about LBJs, Little Brown Jobs, well, his looked like a little brown frog, not particularly exciting to look at, but it was behaving oddly. So he collected it and it turned out to be a new species named Rheobatrachus silus, and he discovered it in 1972, but by 1979 it was extinct.

What was unusual about this frog was that unlike a normal frog which, when they mate the male mounts the female in amplexus they shiver and they shake, the female extrudes her eggs, the male fertilises the eggs, and then they both go off and have a happy holiday somewhere else and they don't care anymore, they leave the eggs to their fate in the pool. Not this frog. This frog turned around as soon as its eggs were fertilised, the female, and swallowed the eggs into her stomach. The discovery of how this happened was extraordinary in itself. But when you think about it, that's bizarre. This frog ends up turning its stomach into a kind of a uterus and it raises the eggs in its stomach, the eggs actually turn into tadpoles, and then the tadpoles actually metamorphose in the stomach and turn into frogs. And then this female, when she can't stand it anymore, she has this mass of seething frogs in her gut, has a huge projectile vomit and just sprays out frogs. And this was extraordinary.

When this was first discovered…David Liem found the thing, but Greg Roberts and Chris Corben in 1973 were very excited about this, went out and caught some of these frocks, they didn't know about this behaviour. They took them home and they had one in a tank of water in the house and they had one of the housemates, a girl who knew that they thought they had some sort of weird aquatic frog, but they didn't know how weird this was, and she was sitting there in the living room while they were in the kitchen getting the meal together, as males should do, and suddenly she looked at the tank and there was a big commotion. And she looked and she saw this frog in the tank that she knew they put in there, and it had another frog in its mouth. And she immediately drew the logical conclusion that it was eating another frog and she screamed at them, 'Your frog is eating another frog in its tank!' And they were in the kitchen totally confused because there was only one frog in that tank. So they came racing out just in time to see this frog suddenly project another frog out of its stomach and then more and then more. And then that's when they began to realise what an extraordinary thing they had.

The frog was studied for a while by Mike Tyler in the University of Adelaide. He was the last person to have a colony, about 40 years ago. And I knew about this, and I went to Mike, I rang him up…Mike was actually at that point in the hospital, he has an autoimmune disease and he has a struggle. And I rang up and I said, 'Mike, 40 years ago by any chance when you had this gastric brooding frog in the University of Adelaide, did you by any chance preserve any of these, did you freeze any tissues?' And when I explained why, that I was possibly thinking about trying to see if any of those tissues could be used to de-extinct those gastric brooding frogs, he got very excited.

And what I didn't know apparently was he wasn't sure, but I found out later he actually pulled all the tubes out of his body in his hospital gown, got out of the bed, ran out of the hospital, grabbed a taxi and ran over to the University of Adelaide in his hospital gown, tubes dragging along on the road, because he was getting really excited as he thought about this. And he tore his freezer apart and, sure enough, he found a jar of frozen Rheobatrachus tissue in the bottom of his fridge at the University of Adelaide. And if anybody knows the problems with universities, the mere miracle here that something hadn't failed in the electricity in that university for 40 years beggars belief, but it hadn't. So the tissue was intact.

So I thought, okay, we should start to think about this possibility, and we put a team together who had special skills that could manipulate frog tissues, and we had a look at the stuff. Mike sent some of the tissues to us, so we looked at it. And even though this had not been cryo-protected, there had been nothing done when he put these tissues in deep-freeze to stop the water in the cells from expanding, as water does when it expands, and destroying the tissues, they looked good. You could see the nuclei, you could see the solid cells. So we thought let's just give it a try.

So we got Mike and he sent us a whole jar full of the tissue, and it turned out, it was interesting, in that jar he not only had bits, he actually had some whole frogs frozen as well. So we had a lot of material to start to work with. What we did, we started to take some of the nuclei out of the cells of this frozen frog and we put them into the eggs of a different…not even a closely related frog but another Australian frog, and in this case we chose a frog that had very large eggs with lots of yoke, and the reason we thought that was important was that these things, that this hybrid cell where we put the nuclei from the extinct frog into an egg of another frog, it had to have enough food to be able to let that frog develop through the tadpole and then metamorphose into the frog stages. So we picked a frog, the great barred frog here that has huge eggs, and we harvested their eggs. You could do this by giving them egg stimulating hormones that cause them to really pump out the eggs. And then with a very fine technology we moved some of the nuclei from some of the frozen tissue cells into these eggs.

We first enucleated the eggs of the great barred frog and that was done in one of two ways. One, we sometimes tried to simply withdraw the nucleus out of the egg, that was hard because there's jelly…the jelly that gets around frog eggs, that sounds like such a simple word, 'jelly', you know, it's what you put on your bread in the morning for breakfast…that jelly is the curse of all of this kind of work with frogs. We couldn't get the needles you had to use through that jelly. The needles would bend, they would snap, it was horrible. And we tried everything to get rid of this jelly. I'm even remembering one day I was there and I put these eggs in my mouth, and I'm sort of washing them in my mouth hoping maybe saliva will dissolve some of this jelly off. There was nothing we could do. Finally we had to find we physically strip off the jelly, but it's like a magic pudding. When you put it back in a solution in a Petrie dish and, bang, there's jelly membranes again around the eggs. It's an amazing material. But eventually we did start to get this to work.

And one of the people who was working with us, Jitong Guo from Mongolia, he is an expert at doing what's called somatic cell nuclear transfer, taking the nuclei out of one cell and putting them into another cell. So he was perfect on this team. But I never, ever saw Jitong smile. He was always the most flat, unresponsive, unemotional person I've ever met in my life. Until one day, about three weeks after we were starting this work after thousands of trials of getting the extinct frogs' nuclei into the eggs, we turned around and there was Jitong's face, and that was…the whole room melted when that happened. And why? Because, bang, one of those eggs had started to divide, and then it divided again and it divided again and it was clearly on its way to producing the beginnings of a frog. And yet the only nucleus that had been involved in this frog was the gastric brooding frog's nucleus. So we were really excited. To make sure of that, we took some of these cells of this blastula, this ball of cells, and we got it DNA tested, and sure enough the DNA in those cells in that embryo was the extinct frogs' DNA. It was back and it was replicating, after 40 years of being technically extinct. So it was very exciting for us.

Suffice it to say, the problem that we have is we do have these embryos. We've had several goes at this and we've produced this now and it's pretty good, so we know we've got the extinct frogs' DNA back, and working, so that's a miracle in itself. We should have no reason to expect that. And we have in these early-stage embryos, the blastula, but in order to go on to produce a tadpole, that ball of cells has got to invaginate, it's got to punch in, like you push your finger into a basketball, to get a two-layered structure. And in order for that to happen (it's a term called gastrulation) the embryo had to continue to develop, and they didn't, they stopped at this point.

So we were immediately thinking, okay, there must be something wrong with the extinct frogs' DNA that doesn't push it beyond this point. But just to be sure we tried doing the same process with a living frog. We took the eggs or the nucleus from a living frog body cell and we put it into the same frog's egg cell. So we did the same process but working with what we knew was perfectly good DNA, and it stops at exactly the same point. So that convinces us that the problem that we've got at the moment is something to do with our technology, it's not to do with the extinct frogs' DNA, that's probably fine.

So now we have stopped and we are re-gearing, sort of taking two steps back in order to move forward. What we are going to do now is work with the living frogs to figure out what we need to do to get past that point to have that cell continue to develop, then we will return again to the gastric brooding frog. So I'm pretty convinced it's going to happen, and before long we are going to have our little frog back again. So wait for that one.

It's interesting that when this happened it got quite exciting, a lot of us all around the world who were working on de-extinction projects were doing it quietly because you didn't want to look like a total idiot for trying something everyone else thought was impossible. So all around the world people were quiet about this, except the people working on the mammoth project, they were pretty noisy. But everyone else was quiet. But when we mentioned that we actually did have this success, bang, the Guinness Book of Records sort of logged this one, the first living embryo grown from an extinct frog, in the 2016 book. Okay, so that project is continuing.

This is a project that I started, and there are many people who are involved in this in one way or another, but kind of going in lurches and bounds and there are big hiccups yet to overcome before we get to a final point, but I think it's something we need to start. And this is the disaster, we are all aware, 7 September 1936, the last thylacine in the Beaumaris Zoo here in Hobart died of neglect. It was a terrible, disastrous thing. The question is, how did this happen to the king of beasts, how do we get to this horrific point?

One of the things, as was mentioned, that we spent a lot of time, the last 43 years actually working these fossil deposits in Riversleigh, it's a World Heritage site in north-west Queensland, and Peter and your team in the Northern Territory museum has been working on fossil thylacines, so we are all interested in the history that led up to this living thylacine that was only found in Tasmania when Europeans arrived. How did it happen? Well, in Riversleigh certainly the fossil communities we were looking at were filled with thylacines, there were all kinds of thylacines. And so they were also through the Northern Territory, we know that too, little tiny ones, medium-sized ones, big ones. It was a very diverse group. If you had to make a guess at that point, 25 million years ago or 15 million years ago, it looked like this was a go-everywhere group, they were doing great things. But it didn't stay that way unfortunately.

We find our fossils in limestone, we dissolve that limestone with acetic acid, and the fossils emerge, they are untouched by the acetic acid and it's absolutely beautiful. This is a little thylacine, Nimbacinus dicksoni, we called the Philosophical Thylacine. It had fallen into a cave, the cave had become a fossil, but it realised it wasn't getting out of the cave, it was a little fox-sized thylacine, it was about that big, and it had just gone from little 15 million year sleep, put its head down on its arms that's how we found it when we dissolved the limestone. An amazing animal.

But that diversity started to decline, and it's a long-term story here that we've been documenting. And pretty soon…and Peter has been working also in Alcoota in the Northern Territory, by about 8 million years ago there were only three kinds of thylacines left. One was Thylacinus potens, the powerful thylacine which was bigger than the Tasmanian thylacine, it was a beauty. But then they continued to decline. And by 3.8 million years ago there was only one kind of thylacine left and that was the first appearance of the Tasmanian thylacine that we know about from Chinchilla in Queensland and a couple of other places.

Okay, the decline continued. By 10,000 years ago, for reasons nobody can understand, they disappeared from New Guinea. They were clearly in New Guinea, they were in the fossil deposits of that age there. And then 4,000 years ago they disappeared from mainland Australia, and we don't really understand why except that there is a terrible coincidence here, that dingoes, the oldest dingoes are about that age, and we know from the genetics of dingoes that they were introduced twice into Australia. There are still arguments about who did it. Maybe the Lapita people, maybe Macassan traders, we don't know. But when dingoes were brought in, almost immediately the thylacines disappeared. And I've heard arguments that, oh no, they must've died of disease and so on. We can't get around this coincidence of dingoes in, thylacines out. So pretty soon the dingoes dominated Australia and the thylacine was in Tasmania because the dingo couldn't get to Tasmania, there was a big water barrier at that point.

Then of course the real disaster for the thylacine started, 1788, when we brought in sheep. If you haven't seen this movie, I highly recommend it, you shouldn't be listening to me, you should be out watching some of these beautiful movies. This is called Black Sheep, and it's about vampire sheep in New Zealand, it's beautiful, and it kind of sums up, I hate to say it, my view about sheep and what they've done to the biodiversity in Australia. It's been a disaster.

But suffice to say we valued sheep, we certainly valued sheep more than we valued thylacine, and by the 1930s…Bob Paddle's book documents about 4,000 thylacines…you know the story so I don't even need to tell you, but they were being blamed for theoretically the reason why the Tasmanian managers of properties here weren't bringing enough money back to England, they needed some explanation for why the English owners weren't making that much money, and they said, oh, the thylacine, oh no, let's not call it the thylacine, let's call it the Tasmanian tiger or the Tasmanian hyena and demonise this animal. And then of course there was a bounty and everybody was out slaughtering thylacines, and about 4,000 of them were killed, and not a big surprise that they went into a massive crash at that point.

This is the first time I visited Beaumaris Zoo, this was about 20 years ago, and I was very interested. This was Charles Wooley, we were down there with Channel 9 doing a story on extinction. He was interested in the orange-bellied parrots, so we were looking in a few places in Tasmania that were interesting. And this is all that's left of the Beaumaris Zoo if anybody has seen that, it's a front gate, everything else is gone, and there is a kind of a metallic, very forlorn looking thylacine in the gate over there.

And of course we know what happened at that point, it was disastrous; the last thylacine that was living there…and there's an interesting controversy beginning to boil up about how many thylacines may have been in the Beaumaris Zoo in these last few years, but that's another story. Suffice it to say, Benjamin, the one that is commonly known, the last thylacine that was presumed to be alive in the Beaumaris Zoo was not allowed to get into its hutch on that particular night on 7 September, 1936, and it was a terribly cold night, and it was immediately stricken with pneumonia, at least what the zoo's records say, and that it promptly died. It was a terrible tragedy.

I thought and I used to say to people when they asked me about this, what happened to Benjamin, the story was that they cared so little about this last thylacine, they didn't obviously realise it was the last thylacine, that they chucked it in the dump. But apparently that wasn't the case, they actually skinned…there was a keeper or a caretaker who actually skinned that thylacine, and that skin of Benjamin is in the Tasmanian Museum and Art Gallery. So that's an important recent discovery. So the museum knows that this is a complicated story.

Okay, you've seen this, this is the footage, it's very famous footage, it was taken by David Fleay in 1933 and it's the best footage of a thylacine that is known. And the Tasmanian Museum and Art Gallery has the rights to this. And it's interesting, I spoke to David Fleay, I knew him very well when I was the curator of mammals in the Queensland Museum. And I said, what happened? And he said yes, it was the most fascinating experience for him. He went into the enclosure with Benjamin and he had a camera, he had asked could he film it and they said, sure. But he was so excited when he got into the cage, he forgot to put the film in the camera. So he was busy madly as the thylacine was sort of walking around. They are really nice, gentle, sweet animals. He got kind of flummoxed, but as he was putting the film into the camera, Benjamin, he said, came around behind him and bit him in the bum. It's kind of like the last thylacine's last statement about what humans have done to thylacines. And I did ask him at that time, 'David, did you keep those trousers?' Thinking there might be saliva on those trousers. But suffice it to say, no.

When you think about this whole proposal of trying to get thylacines back, we often get hit with this comment; well, you're kind of wasting your time, you know, because they are still out there. Somebody did say this, that they were aware they had seen a thylacine, and I have friends in Tasmania who will swear that they have seen them. And I have investigated so many of these claims, mostly on mainland Australia where people have said that they've seen them.

And this was one of the most famous. This thylacine came out of a place called Thylacine Hole in a cave on the West Australian Nullarbor. David and Jane [Jackie] Lowry found this specimen, and it was perfect; the eyeballs were in it, the nose was in it, the tongue, it was absolutely perfect. Right next to it was a rabbit that looked exactly in the same condition. And they drew the very reasonable conclusion that this thylacine had fallen into that cave only a matter of weeks before.

And immediately the National Parks in Western Australia went about the process of starting to set up a national park to protect the thylacine on the Nullarbor because everyone was suddenly convinced it was still there. Until a palaeontologist, Duncan Merrilees in the Western Australian Museum thought, hmm, let's just be dead certain about this. And he said why don't we just radiocarbon date a piece of it, and they did, and it was like 4,000 years old. So one mystery gave rise to another. How did that happen? As they had it in the museum it was beginning to decompose, the eyes collapsed, the nose started to go. It is now stored, what's left of it, in an evacuated container so that it's frozen, it has stopped decomposing anymore.

But somebody, one of you guys, one of you entrepreneurial students here looking for something to do, while this is a sad loss and an eye-opener, there is a fungus in that soil in Thylacine Hole that if you get it out and you get it into a face cream, you're going to get people's faces protected for 4,000 years, they'll stay the same. Somebody has got to think about things like that. This is biomimetics.

At any rate, another person who is convinced it's still out there is my good friend Col Bailey who I have enormous respect for. Col's most recent book, The Lure of the Thylacine, I actually wrote the introduction for that book. He and I, we've gone bush, hunting for thylacines in areas where he is quite convinced they had been recently found. And Col said he is actually convinced that he has smelled them, and in the book he actually reports having seen one. It's that kind of apocryphal situation where he was having a pee in the bush and of course as he was having a pee a thylacine poked its head out right next to him. And of course he didn't get his camera out or anything else. He probably got wet trousers out of it as well. But he was convinced it's there.

So he and I have made an agreement, and the agreement is if he finds a thylacine, if he can capture one, he promises he's going to send us fresh tissue so we can clone the thylacine with fresh tissue. And we've said in exchange if however the thylacine is cloned back into existence first, we promised to release it in his backyard so he can find it first. And this seems like a very reasonable early contract that we've made.

Assuming that it is extinct…this was the first specimen that excited me. It was a pickled specimen in the Australian Museum's collections. I was working on my PhD in about 1990, it was a little after my PhD, but I was studying thylacine skulls in the museum, and I saw this specimen on the shelf leering down at me, and I could see it had stripes, it was a little tiny girl thylacine, it was collected by George Masters in 1866, and for some reason or other this early collector had pickled this specimen in alcohol. We don't know, maybe it was brandy. You don't usually do that in that time period, but he did. And he sent this time capsule into the future.

As a palaeontologist, I did however know that alcohol was a DNA preservative. So I immediately, 1990, I went to my genetics colleagues and I said, 'Guys, why couldn't we think about reaching into this specimen and recovering its DNA and then think about going down one of these paths?' The laughter, it was painful, I remember it, and it was scarring, like, 'Go back to your fossils. This is impossible.' But that was 1990 and it was before Dolly the Sheep was cloned. So all kinds of things happened subsequent to that question that would have been required to be part of a process of trying to recover an ancient animal's DNA and using it to bring the animal back.

And Ian Wilmut, very quiet, nobody knew he was doing this because everyone was convinced you couldn't clone mammals, suddenly cloned Dolly the Sheep. I don't know how many people are aware why Dolly the Sheep got called 'Dolly'. What they did was they took a body cell, the nucleus from a body cell of a sheep, it was standard cloning, and they put the nucleus into the egg of a sheep. So they made a hybrid cell of that kind. That was cloning from one individual to another, and they got Dolly the Sheep, it worked. But what I found out was where they took that body cell was from the udder of the first sheep, and they thought, who has the most spectacular udders in the world? Dolly Parton of course. And that's how she got named Dolly actually.

But there were all kinds of dark sides. I notice Bernie Hobbs actually made this comment at that time: it's been 2,000 years since there was this much fuss over a birth in a stable. And it's true, the world went gaga when Dolly the Sheep was popped out. And everybody thinks, okay, this is cloning, what did they do? They took the nucleus from a body cell of an adult sheep. So already that cell was as old as that adult sheep. And they made an embryo out of that. So the presumption was you started out with the youngster that was already old. So they expected Dolly to die of old age early, and in fact many people still assume that, that Dolly died of premature old age. But she didn't. I've actually talked to the people who were looking after Dolly, she died because she was housed, stupidly, with another sheep that had an infectious fatal lung disease. She died because she caught that disease and that's what killed her. There was nothing wrong with Dolly. Yes, she did have a tiny bit of arthritis, and the guy who was looking after her said it's not surprising because everybody who came to visit this miracle mammal was given a sheaf of wheat, and there were thousands and thousands of people who did. They went over to the pen where Dolly was and held this wheat out and Dolly got up on her hind legs to eat the wheat. She spent 50% of her day walking around on her hind legs. Not a big surprise she had a little bit of arthritis in her pelvis. That's not normal for sheep. But otherwise she was fine. And she went on to have a little sheeplings, lots of them, she was doing well.

Bob Lanza who works with Advanced Cell Technology in Boston, when I asked him a lot about this idea that somehow if you took a nucleus out of an adult body cell, does that mean that you're going to start with an ancient animal when you get a hybrid like that? He said no. This is one of the lovely things about this research area, things happen sometimes that you can't predict. And he said in fact he knew about these cattle that had been cloned, and now there is all kinds of agricultural cloning going on automatically. But he said they looked at the telomeres, those little caps on the end of chromosomes. If you want to know how long you're likely to live in probability, you get your chromosomes and you get somebody to measure the length of these caps on your chromosomes and you'll get some idea about how long you've got to go because every time your cells divide, a little bit of damage occurs on those telomere caps. So as you are older they are shorter, when you're young, they are very long. These cattle were born with telomeres that were 30% longer than normal cattle. Arguably they are going to live longer than normal cattle. So there's all kinds of anticipated presumptions here that have not been supported.

And there's a lot of interesting research going on about telomerase, the enzyme that's involved here. There is recent research showing that you can actually take ancient old mice, mice that are prematurely old and really look like they need a walking stick, and they inject them with telomerase and they end up reversing. It's Benjamin Button syndrome, they actually get younger and younger. So of course people are very interested in this research. Is this something that we can extend to humans? No, not comfortably yet because apparently it's also associated with an increased risk of cancer in humans if you have too much telomerase, so there is more distance to go here.

I was still told even though we were getting more interested now, yeah, you're never going to be able to do it. Yes, they clone cattle, yes, they can clone horses and so on, but they haven't cloned carnivores. And then, bang bang, 2001, CC, for Copy Cat, all of a sudden there was a cloned cat. And in fact if you are interested, it only takes $25,000 right now, you can shell out that little amount of money and you can get your moggy back if you really love your moggy, they can clone your same moggy back.

And, fascinated by this whole possibility, I contacted people who'd had this happened. And I said, you've got a cloned cat…they actually had paid $50,000 to get a cloned cat. And I said, well, what do you think about it? And they were absolutely ecstatic. They said the cat was, despite epigenetic variation, almost identical to the original cat. And she said when the mouth was open…you know, cats have this grey and pink pattern often on the roof of the mouth, she said that pattern which was distinctive in her cat was there in the roof of the mouth. And then she told me something I wasn't sure I really wanted to know, she said it even kisses the same. So, okay. At any rate, you can do it.

And not only that, now they are doing it with dogs as well, it cost you a little more to get a cloned dog, but if you really love your pooch, you just pluck out a hair…on the website…it's South Korea that's doing this, you can get an animal back and, as they say, there's over 700 cloned cats and dogs out there already and the numbers are escalating rapidly.

Okay, when all this started happening I thought, bugger it, I became a director of the Australian Museum and I thought nobody is going to tell us at this point don't do it because it can't be done, we thought let's just try it. So we put a team together, and in particular Don Colgan and Karen Firestone are the two geneticists involved, they were spearheading this particular work, and we went into that pickled pup that was in the Australian Museum collection and we did get DNA. Mind you, we did to get an awful lot of human DNA that was in that pup as well. Every curator who had ever worked with that collection had thought, wow, put their big fat hands into the jar, pulled out this thylacine, look at that, and dropped it back in the jar. So there was a lot of human DNA. And the worst thing that we could imagine, if you go through this whole process, you recover all the DNA, you put it in the machine, you turn the crank and out pops this wizened old curator out the other side of the machine.

So what Karen did when she realised we were getting thylacine DNA, no question about it, but not enough of it yet, and she actually went into the teeth of museum specimens, and this begins to tell you how important museum collections are, they are reservoirs, they are DNA arks for all kinds of extinct animals just waiting for the technology to get better and better. And now I've just been told by one of the leaders in this research area coordinating with George Church in Harvard University, that they are spearheading technology for getting long, long sections of DNA, not just the reconstructed DNA sequences but the actual DNA itself out of dry tissues. So this field is advancing very, very fast.

At any rate, what she did was she drilled into the teeth where bacteria have a harder time getting in to degrade the DNA and she got much better quality DNA. And we started to work with a lot of this stuff. We found that we were able to get it to go through polymerase chain reaction. I was told that wasn't going to be able to happen. We weren't going to be able to identify genes, we did nuclear and mitochondrial genes. And in fact there was one, without mentioning him, one stem cell researcher who every time…and we were out front with this project while I was in the museum…every time we made a breakthrough, he would race to the newspaper and say, 'Yeah, yeah, well, why wouldn't you expect they could do that but they will never do this,' and that would be the next step in the process. And then we'd do that. And then he'd say, 'Oh yeah, what would you expect,' and then he came out with another article. It was only negative, negative, negative: but you'll never get the next step. And we kept doing it. And after about three of these little rounds the phone rang, and I picked it up and it was him. And rather than going out to the newspaper at that point, all he said was, 'Can I help?' And I thought, wow, okay, he had sort of come full circle and he wasn't laughing anymore, it wasn't as impossible as he thought. And in fact some of the advice and help he has given us has help us move into the Lazarus Project.

Would this pickled DNA work? And here's a fascinating thing that has happened with Andrew Pask here and Marilyn Renfree and a whole group of people in the University of Melbourne. What they did was they took some pickled thylacine DNA, they spliced it into a mouse genome with a kind of a tag that if that thylacine DNA had actually worked, if it produced thylacine tissues, that tissue would be blue-green and in the pups of the mouse when it gave birth. And, bang, those little pups were filled with blue-green tissue, thylacine tissue.

We all got very excited when that happened. It meant that if you get this DNA back into the system it's going to work. It's only a matter of time. Of course I did ask what happened to these pups? They had thylacine beginnings, so for all we know they would have been mice that came out with black stripes, but they had to actually euthanise them because you're not allowed to have transgenic animals beyond a certain stage in development. So, legally they were required not to pursue the work. But at least it said to us that if you get this DNA back into the right situation, it's going to work. And now Stephan Schuster of Penn State University published the whole mitochondrial genome of the thylacine, and now Andrew has published the whole nuclear genome of the thylacine. So basically the core aspects of the recipe for a thylacine have been published.

How would this work? And this is such a simplistic, ridiculously silly explanation, but this is the principle or one of the principles that you could follow. One, you would take a host egg of some animal and you would annihilate the nucleus of that host cell, just like we did with the Lazarus Project, and then you would take the reconstituted thylacine DNA, either an artificial chromosomes or however that was going to work, and you electrofuse that in the enucleated cell, a little spark. This is standard technology for doing this, for fusing two parts of cells together, it works easily. And then you would get an embryo then you would plant that embryo, that early embryo into a host, and one of the obvious hosts would be would be the Tasmanian devil, that same kind of size. I did hear that this is going to be difficult because you think thylacine, Tasmanian devil, that's going to hurt when they give birth. But you forget it's a marsupial, and a thylacine is going to pop out about the size of a small jellybean, so that Tasmanian devil is not even going to know it has given birth. It is going to think it's got the ugliest Tasmanian devil baby as it starts to grow up. But that's one possibility.

Andrew suggested you might equally think about a numbat. The reason I think that the Tasmanian devil is a more likely candidate is we know more about the genome of that animal already because of the interest of the facial tumour syndrome problem. Then you plop in the embryo, and, bang, out the back end of your host comes a thylacine, that would be the theory.

Is this a risk? You've created kind of chimeras. You know, you've got the nucleus of one animal, you've dropped it into the cell of another animal, are you going to get some kind of bizarre hybrid? And the answer is no. The only nuclear DNA involved in this hybrid is the nuclear DNA of the thylacine. The only thing that can pop out the back end of that host is a thylacine. So that's not a problem. The bigger question, and there are a range of questions here, if this did work down in the future, if we actually get it back, could we put it back in the wild, or is it doomed to be a zoo animal or some kind of curiosity in the laboratory? Could we actually get it back into the habitat?

This man, I met him in 2001, Peter Ward. Peter Ward actually with his brother and his father caught thylacines, and my conversation with him is one of the magic moments in my life, listening to him talk about these experiences, it was fascinating. And I said, by any chance did he remember where he had done this, where he had caught these animals, where they had been trapped? And he said he thought he might. He was 90 at this point, he was getting on. And I said, 'Can you show us the track?' And he did. And he took us down this forest trail and, sure enough, there was the hut that he and his brother and his father built. Inside were little slabs of wood where they slept at night, in the back was the drying shed where the skins were dehydrated. And he remembers everything about it.

Why was I interested in this? Because I wanted to know, looking where he caught these thylacines then, what did he think about what that area was like now? Was it different, had it changed, or was it still the same kind of area that he remembered as a kid when the thylacines were there? And he said it was absolutely identical. In the back were southern beech forests, and this is a standard thylacine kind of a situation. By day they would be hunkering down in the edges of the forest and at night they would be out in the grasslands, that was snow when we were there, they'd come out and hunt in the grasslands for small animals. So he said it was exactly the same way, and the parks people have told me the same animals that thylacines ate, naturally, are still there. So the habitat still exists, both in southern and northern Tasmania.

Five reasons why we would try to bring this back. One, I mentioned the moral responsibility. We killed this thing and we just have to accept that. So if we feel guilty about it and technology gets us into this corner where we might be able to do something about it, why wouldn't we?

Ecosystem stability. This is becoming an extremely important rationale for de-extinction projects. It's not just about getting an ancient animal back, but it's getting an animal back that can do something important in the ecosystem that is missing, and the classic example is what happened in North America when they eliminated wolves from Yellowstone, the ecosystem started to collapse, the elk numbers built up, they overate the vegetation, water eroded the river systems, the whole park started to collapse, so they brought the wolves back. And suddenly the park has been stabilised and it's working extremely well.

Now, the thylacine is our king of beasts. It would be the same thing. We've pulled out a key member of the ecosystem down here. And not surprisingly we may have cascades of extinction problems that may take a while to show up. But one of those problems could be the facial tumour syndrome of the Tassie Devil. Before the thylacine was exterminated, it competed with the devil for food. The devil was in isolated populations. When that disease popped up, and it probably did frequently, not just once, it would have burned out in a regional population because those populations were not in contact with each other. But we pulled the thylacine out. And then devil numbers build up and all of a sudden you have one devil population where that disease could threaten the survival of that species, so that's another important feature.

Cross species technologies…in learning how to do this technology, we are actually doing something extremely important that can help endangered living species. We can use these cells of endangered species, body cells, to start to increase their numbers using the host that's more common, a closely related host. So the technology is highly relevant to modern conservation of endangered species.

Ecotourism. Can you imagine, when we started playing with this project, I came down to Tasmania with John Shine actually because I wanted the credibility of a geneticist talking with me to the politicians in Tasmania, and I won't mention who they were at that time, but they were busy chewing up the Styx forest and turning it into woodchips and sending it off to Japan. And thylacines were in that area. So we came down and said, look, if you will not destroy this forest, we will commit down the road, if thylacine can be brought back, to releasing it here and you can call it the Thylacine Forest. And think, just do the sums of the money that will be paid in ecotourism for people to come and see living thylacines brought back from the dead.

Politicians got quite excited, most of the lesser politicians anyway. The museum was supporting it, National Parks was supporting it, they checked with everybody, but the Premier at the time said no, it's going to be woodchips or nothing. And that was it, we went home without a deal, and there it is.

And of course if the Thylacine Project does work, there's all these other mammals that are sitting in jars in a museum that have got their little toes pressed against the side of those jars, keeping their little fingers crossed that they might get a second chance in life. There is a wide range of projects like this going on around the world. One of them is the mammoth project, which I think most of you will have heard. Fascinating project. Another is the Iberian Ibex, it's a very special kind of a goat that lived in Spain. Aurochs, people are trying to bring that back, passenger pigeons, woolly rhinos. Even plants, the American chestnut which has nearly vanished is now a focus of Revive and Restore, a de-extinction group. And yes, there are some people who are trying to bring back more classical dinosaurs, so there's a lot of interesting controversial projects going on out there.

The Iberian ibex, the bucardo, this is one very brief sad story here. Celia was the last bucardo in Spain. People shot them to death, they used to go out sport hunting and there was no sustainable use here going on, it was just mass slaughter, until one was left. And as the biologists began to realise this, particularly Alberto here who is a friend of mine now, they caught Celia, and just on the off chance they took tissues of Celia, and literally the next year a tree fell on her. They had a radio collar on it and suddenly it wasn't sending a signal, and they went out and Celia was dead.

So they straightaway set to using her tissues to create hybrid cells between the nuclei from Celia's tissues with the egg cells of another kind of a goat, and it worked. They got an embryo and the embryo came to full term and was born. But it did have a lung abnormality, nobody knows why, and it didn't live long. But this is not an unusual thing in goats, it does happen. But they were going to do the project again. And I talked to Alberto about this, but suddenly…this is why you have to be political about these things…suddenly the Spanish government did a strange thing, they introduced to the habitat where the bucardo was going to be released if they got a herd back again, another kind of a goat that filled the habitat up. Suddenly there was no place to put the bucardo back again, and so they've shelved the project. They were the first people who actually…and we are talking here 2003, to actually get a cloned mammal back, a de-extinct animal back. That didn't live long but it was the beginning.

The mammoth one, I was going to mention a couple of points about this. Why would we bring mammoths back? A lot of interesting reasons. Sergey Zimov, a fascinating character actually, who started this whole project, he literally has got Pleistocene Park going in Siberia. They bought vast amounts of land, and the idea is to try to get these Pleistocene giants back into Siberia for ecological reasons, not just the de-extinction thing. Their argument is if you get mammoths back, they push over trees, they actually support the growth of grasslands. And grass actually doesn't absorb as much solar energy, it reflects more than trees do. So the argument is you are in fact going to be sending most of the solar heat back into space that trees would otherwise be absorbing. So they will be helping to cool the world.

Another thing was that they are heavy animals, and as their feet punch into the tundra, this lets this bitter cold Siberian air go down into those holes and keep frozen under there this stuff, clathrate, frozen methane. That's one of the big bugaboos, the big potential tipping points that climate scientists are scared about. We don't really know what's going to happen when all this frozen methane begins to start to release. And it is releasing spectacularly. There are all these gigantic blisters in Siberia. Look at this crater that just blew up because this massive amount of methane just blew up underneath it and erupted out like a volcano. So Siberia is starting to release enormous amounts of greenhouse gases into the atmosphere that nobody anticipated. Their argument is mammoths could slow that process down by keeping the ground colder.

Biodiversity, you're adding species back into the world and, as I mentioned, developing new tools for conservation. We have this problem now with northern white rhinos, there's only two of these individuals left, they are senescent. The southern white rhinos are very common. Somatic cell nuclear transfer, the way that we are working with the frogs, this could theoretically save the northern white rhinos by taking the nuclei from body cells, and this work is now going on, this is starting to be done, and injecting it into eggs of southern white rhinos. Of course there are huge issues. You have enormous animals here, manipulating their reproductive systems is not easy. It will be a problem for the mammoth project as well.

And then the last feature is remember that scene in Jurassic Park when they first encountered the dinosaurs, the look on their face, Sam Neil fell over and he couldn't stand up, it was a beautiful reminder of this 'holy crap' factor that would be massive amounts of tourism if you could get mammoths back, and that would mean money and money that could be used to help conserve and maintain complex ecosystems. Any downsides? There is one; car insurance is really going to go up.

Okay, last point; if we do bring thylacines back, is this just about putting them back into the bush and restoring the ecosystem? And I would argue not. It is interesting that the colonial experiences with thylacines suggest that they are very different than the common impression. They were actually very gentle animals. This kid was sick in bed, and he woke up to find an adult thylacine had come out of the forest, come into the hut, and went over to the bed and was licking him on the face. It wasn't…no salt and pepper and knife and fork, it was just licking him, kind of, 'you're nice'. And he reached up patted it and it went over and curled up in front of the fireplace and went to sleep, until an hour later when the father came home and beat it to death with a lump of wood.

These animals were ready to cross the line. And Bob Paddle in his book, and I know he's got another book in the pipeline, focused on thylacines as pets. People were keeping them as pets. Many of them were turned in…it was illegal, and when they finally had to give them up, many of them had collar marks around the neck, they were clearly valuing them as pets. They were thylaco-watchdogs or whatever, but very friendly, very nice animals. And this is the sad thing to me; if it had not been illegal to keep them, would they be extinct today? And the answer obviously is no. Nothing we've ever put our arm around has ever gone extinct. It's things we assume are going to be fine on the other side of a fence, they are the ones that disappear.

And I think there's a message here for all of us involved in conservation, to stop thinking about the idea that somehow the worst thing we could do for an endangered animal is have any human interaction with it. We actually probably have to get humans and the most endangered animals back together again.

A snake, and the Northern Territory Oenpelli python was going extinct until finally the parks people gave permission for reptile breeders to collect a few and now there are thousands and thousands of them. The Wollemi pine, the pinosaur, which was going to go extinct with one bushfire is now in every second Australian's backyard. I've got one. It will never go extinct. We have to get closer to the very things that we are afraid our familiarity would endanger. It's the opposite, it's the other way around.

So, are we inappropriately playing God by trying to bring the dead back to life? Another common challenge that we get. Never trust a professor quoting the Bible, but I've got to get this one in there: 1 Corinthians 15:26, The last enemy that shall be destroyed is death. Ta-da! As far as I'm concerned, we're just obeying orders.

And that's it. As far as I'm concerned, what de-extinction is about is just trying to restore that balance of nature that we've upset. Thank you very much.

Robyn Williams: A lecture put on by the Australian Academy of Science at the Beaker Street Festival in Hobart, finishing, as ever, with a scientific brass band. You heard Professor Mike Archer, from the University of New South Wales, world renowned palaeontologist and winner of the Romer-Simpson Award, the top medal in 2019.