No one has seen a live Tasmanian tiger, or Tasmanian tiger, since the 1930s. But geneticist Andrew Pask from the University of Melbourne believes that this is only a temporary condition.
“One day we will witness the revival of extinct species of animals. We’ll live to see it. There is no doubt about that,” says a scientist who wants to trick nature with his team and create a new Tasmanian tiger by modifying the cells of animals of related species in an interview with Seznam Zprávy.
Pask hopes to have her first cub within 10 years. Subsequently, he wants to create many more and return the bagworms to their native ecosystem in Tasmania.
You strive for so-called de-extinction. Different people explain this term in different ways. How do you understand him?
We use the word deextinction mainly to emphasize the difference from cloning. When someone clones an animal, they need a living cell from which to make a copy. But this cannot be done with extinct animal species. When an animal is dead, its tissues are dead too, and we don’t get living cells from them.
Deextinction works differently. It is still true that we cannot make a dead animal alive. There is no way to reactivate dead DNA. But we can look for the closest living relatives in nature and grow our own cells from them. We then compare their DNA with the DNA of an extinct animal and look at all the signs in which they differ. Then we go back to our cells and edit them to erase those differences.
How do scientists save animal species from extinction?
Scientists are developing advanced assisted reproduction methods to save the northern white rhino from extinction. Recently, they succeeded in creating pluripotent stem cells of the deceased female Nabirá from Dvor Králové.
The moment one succeeds in transforming one’s own living cell into a cell corresponding to a Tasmanian tiger, a living animal can be obtained through stem cell work and cloning.
You said you can’t clone a dead animal. Is this absolutely true, or could even dead tissue be usable under certain circumstances?
In an animal that has been dead for at least a hundred years or so, the DNA is too damaged. The tissue could only be used if it had been frozen to about -100°C or more. We can do something like this now that collecting tissue from endangered animals allows us to store powerful freezers for future generations. Even 50 years ago, this was not possible.
How did you get information about Tasmanian tiger DNA?
We were very lucky to find an incredibly well-preserved DNA sample in a museum in Melbourne. From it, we sequenced its entire genome. We’ve already done that. It is possibly the highest quality genetic information ever obtained from the DNA of an extinct species of animal. We have excellent material on our hands to start a de-extinction project.
What kind of exhibit was it and where exactly did you get the sample from?
It was the body of a Tasmanian tiger cub removed from its mother’s pouch and placed in alcohol. We took the sample from the liver.
You might also be interested in the fact that when we searched the world for all possible exhibits of Tasmanian tigers, we discovered that the body of the youngest individual is kept by the Faculty of Natural Sciences of Charles University in Prague.
I would be very happy if I could come to Prague one day and see him.
Some experts claim that the result of de-extinction cannot be a real representative of an extinct species with exactly the same characteristics, but necessarily only an “imitation”…
I don’t agree with that. The meaning of the term de-extinction is debatable and everyone can understand it differently. However, I have already said what it means for us and I stand by it. We can edit the whole genome down to small sections at the very end and in the middle of the chromosomes. But they have more of a structural function. This means they help the DNA stay together and not fall apart and are not essential for making an animal.
So we are very confident that we will create a Tasmanian tiger. It won’t be some weird looking hybrid.
If it turns out that those mentioned sections of the genome will be essential for certain characteristics of the animal, we will go back to the laboratory and work on being able to rewrite those as well. I believe we can do that too. According to the results of all our work so far, this will not even be necessary.
No one has ever succeeded in de-extinction, what makes you believe that you can do it?
I think older projects failed because they didn’t have today’s technology. That’s the first really big thing. We just weren’t that good at sequencing and editing DNA before, but it’s really gotten a lot better in the last decade or so.
Another aspect that works in our favor is that we are trying this in a marsupial. This order has a much shorter embryo development time than most other and especially large mammals. The entire development of a Tasmanian tiger embryo takes about two weeks. It makes it much easier for him to make a living baby out of a cell.
These are all huge advantages, plus we have the aforementioned great genome. I think we have a good recipe for the revival of the Tasmanian tiger.
If you succeed, what will it mean for science?
That de-extinction is possible, the technology works and can be applied to other species as well. That is our main idea. It would change the way we think about protecting species from extinction.
The point is that many extinct species used to help maintain the stability of ecosystems. If they returned, it could protect other species from extinction. And this is also true of the Tasmanian tiger. It’s not just that we want him back because we fished him out in the past. After it disappeared from Tasmania, we can observe the destabilization of the ecosystem, which could be corrected thanks to its return.
All the technologies we are working on, such as genome editing and creating marsupials from cells, will also find other immediate uses. At the moment we have fires in Australia that are destroying large areas and can threaten the existence of various animal species. Thanks to the technology we have tested, we will be able to take, for example, samples from frozen koala tissue and use cloning to bring them back, even if they all burn.
Advances in genetic modification can also find use. Marsupials in Australia are currently threatened by one species of toxic frog that came to us from abroad. Our animals are not resistant to this frog, but it would be enough to add a single gene to make them resistant. This would not only support their survival, but also reduce the numbers of poison dart frogs, which represent an ecological disaster for Australia.
Interview about genetic modifications with a Czech scientist
The possibilities and limits of genetic modifications were the central topic of the News List with Helena Fulková, the first Czech woman to clone a mouse.
If you really want to return revived animals to the ecosystem, how do you want to address the problem of low genetic diversity?
Of course, we can’t get by with just one genome and one animal. Once the first one is done, we’ll have to move on.
There are hundreds of exhibits around the world, including the one you have in Prague. We can learn a lot from them about the genetic diversity of this species. We can then create the same diversity in other individuals, and thus establish a healthy population.
If you succeed in reviving the Tasmanian tiger, what will be the limit to applying the technology to other animal species?
From a technological standpoint, our procedure should be applicable to any recently extinct animal for which we have sufficient DNA sources.
In practice, however, it is more complicated. I think we have to be very careful what animal we bring back. Of course, we should only do this for those animals that died out because of humans. Another limitation is the preservation of their ecosystem. For example, the Tasmanian tiger will not be a problem to return to where it used to live, because its original ecosystem still exists after about 80 years. But this does not have to be true for every animal.
Your project is referred to as “financially demanding” in the media. How did you get the funds for it?
I have been working on this project for about 15 years, but we only got the necessary funding in the last few months. First we received a donation of five million Australian dollars from a philanthropist (over 84 million Czech crowns, editor’s note). The funding was spread over ten years, so we said, “Let’s do it, we’re going to bring back the Tasmanian tiger.”
Shortly afterwards, the company Colossal, which is working on reviving the mammoth, contacted us with an interest in cooperation. We took them on board and now we help each other. For example, genetic modification is less of a problem for Colossal than it is for us, since it is easier for an elephant than for a marsupial. The development of a tiny Tasmanian tiger embryo is easy for us because it only takes two weeks, but it takes 22 months for a mammoth. We each face different challenges, but we believe that cooperation can help us solve them.
How expensive is the project?
In total, the launch of our project came to tens of millions of dollars. It’s expensive, but I think people who urge us to put the money into protecting species in the classic way are misunderstanding it.
Every bit of research we do here can make a real difference to species conservation. In addition, we ourselves do not draw from the resources intended for this and do not impoverish conservation funds. We are funded by philanthropists and commercial companies. Not only do we not take money out of species protection, we bring it in.
There will also be scientists who call your efforts an attempt at the impossible, science fiction, a fairy tale, and so on. What would you say to them?
That in reality our planned course of action does not include anything that is not already routinely done.
We are not developing something completely new. We apply already existing tools and technologies. No one can say that gene editing and cell creation is a problem today. And that’s exactly what we want to do, just on a massive scale.
Of course, this presents some problems, but only time and money are enough to solve them. That is why I say that one day we will witness the revival of extinct species of animals. We’ll live to see it. No doubt about it.