The woolly mouse: A fluffy new species created from mammoth DNA

They fit just inside the palm of your hand. They’re blondish-brown and incredibly fluffy. They’ve got a tail as long as their bodies, adorable soft, round ears – and, until recently, they didn’t exist in the world.

These little creatures are called woolly mice. They were created in a lab crossing woolly mammoth DNA with that of a lab mouse. Colossal Biosciences, the Dallas-based biotechnology company that created them, says it’s the first step to resurrecting the woolly mammoth – which the company aims to do along with two other extinct species: the dodo bird and thylacine.

Chief Science Officer for Colossal Biosciences, Beth Shapiro, spoke with Texas Standard about the new mice, the reasoning for bringing animals back from extinction and the possibilities this adds to conservation. Listen to the interview above or read the transcript below.

This transcript has been edited lightly for clarity:

Texas Standard: Well, I mentioned some of the traits, but what are the other unique traits of these new mice?

Beth Shapiro: Well, we are focusing with the mice on some of the important traits that we will need to alter in a tropically-adapted Asian elephant in order to transform it into an Arctic-adapted mammoth. So we’re focusing really on traits that will help it survive in cold climates with these mice – the coat, the texture, the length, the density of the coat.

We altered the coat color because we wanted it to look a little bit more like mammoths that we see melting out of the dirt in the Arctic. And we modified a gene that should alter the way that they metabolize different types of fats, hopefully to, again, help them to adapt to colder climates.

Well, explain in layman’s terms the science behind all of this.

So one of the things that we’re trying to do is figure out exactly what sequences in the DNA code of an Asian elephant we will need to alter using the tools of genome editing/genome engineering to turn it into a mammoth.

So we do this by going out into the Arctic and collecting a load of mammoth bones and we extract DNA from them and sequence their genomes. Then we align them to each other on a computer and we compare them to the DNA of elephants and we ask ‘where are all of the mammoths the same as each other, but different from the elephants?’ And this is our list of the genes that make a mammoth a mammoth.

It’s not possible to bring something back that is 100% identical in every way to a species that used to be alive. So we’re targeting characteristics – in this case, the coat, like we were talking about.

And then this is where it gets hard. So we would love to be able to test our ideas using a whole animal. Fortunately, we have something that is related to an elephant, and that is a mouse. And we looked at this list of genes in a mammoth.

Then we cross reference that with a list of genes that we know impact the coat in a mouse and so we identified places where there was the same gene that looks like it should make a mammoth wooly and – we have seen, in a lab somewhere else – made a mouse wooly. And we collected all of those different genes and put them together in the same mouse to make our colossal wooly mouse.

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Courtesy of Colossal Biosciences

Why bring back an extinct species?

For each of the three species that Colossal is targeting – and that is the mammoth, the thylacine, which is also known as the Tasmanian tiger, and a dodo – our goal is to create proxies for those species, functional replacements for those species that we can put back into their habitats.

The thylacine was the top predator of its ecosystem until it went extinct because of human hunting a little over a hundred years ago. And there isn’t another predator to put in its place. And if we look at the wolf reintroduction program in Yellowstone today, we can see the incredible impact to the ecosystem of adding that animal back into that landscape.

So by replacing these species in the ecosystem, we hope to restore interactions between organisms that helped that habitat be more robust and resilient. But the additional benefit, to me, is that along the path, we will discover new tools – new ways that we can help species that are still alive, but in danger of becoming extinct.

Well, so there are some who say let nature take its course and there’s a reason species died out. And you also referenced that there is a role of humans spurring the extinction of species. Is this a way to right that wrong?

I think it is a way to more fully arm ourselves against the disasters that are happening everywhere on the planet.

You know, when people first dispersed out of Africa and around the world, we do see in the fossil record that there is a lot of extinction that is caused by people arriving. And then we started modifying species in different ways – domestication, agriculture, even the way we protect and conserve species today is humans messing with the species around us.

What we’re trying to do, the movement into more precise genome editing tools and biotechnologies, is a different way of people sort of meddling with nature that’s out there. But it’s a positive benefit.

And it’s not a replacement for traditional approaches to biodiversity conservation. Certainly, we need to keep doing the things that work. But we should also be growing the number of tools we have in our toolkit for protecting species and habitats today.

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