Mammoth reproductions in the visitors' center Ark Nebra in Nebra, Germany, March 29, 2012. (AP/Jens Meyer)

"Does this mean we can clone a mammoth?": The tantalizing, risky and very real science of de-extinction

Biologist and author Beth Shapiro on the dos and don'ts of bringing extinct species back to life


Lindsay Abrams
May 9, 2015 11:00PM (UTC)

Beth Shapiro is an evolutionary biologist specializing in ancient DNA, a complex field (which she pioneered) that uses genetic information from long-dead species to learn how past populations responded to previous periods of rapid climate change -- lessons she hopes we might use to preserve biodiversity today. But every time her lab publishes research relating to the reasons why the mammoth went extinct, she told Salon, someone calls her up (sometimes it's her mom) and asks, "Does this mean we can clone a mammoth?"

"I just got so tired of answering that question," Shapiro said, which might strike some as a strange reason to go ahead and write an entire book about it. But that's what she did. The result, though titled "How to Clone a Mammoth," answers the question pretty quickly, with a definitive "no." Still, she found a lot to discuss -- because while we will never see the day when mammoths once again roam the earth, the science of so-called de-extinction is real, and tantalizingly close.

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When it comes to de-extinction, Shapiro positions herself as an "enthusiastic realist": she's excited about the possibilities, but wary of the potential for abuses. She does not entertain questions referencing Jurassic Park. And if we're going to get serious about this technology, she warns, there's a lot we have to consider first.

Our conversation, lightly edited for length and clarity, follows.

De-extinction: I was hoping you could start by just explaining where we are in the realm of feasibility when it comes to this?

We can’t bring any animal that is extinct back to life, and we will never be able to create a 100 percent identical copy of an animal that has been extinct for a long time. Where we are in the process of creating animals that are copies of something that was once alive depends very much on what animal you’re talking about. With every species that one might consider for de-extinction, there are different technical, ethical and ecological challenges that one might encounter and will need to address.

As you reveal in the book, the title is a little misleading, because we’ll never actually clone a mammoth -- at least not the way people imagine it happening.

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Right. When people think of cloning, what they’re generally referring to is this specific scientific technique where you take the genetic material from a living cell and you insert it into an egg cell that has had its own genetic material removed. This is the process that brought us Dolly the sheep in the mid-1990s. It’s an excellent process, it’s been used on lots of different species and people have been refining it since that time. This is a technology that has been used with success in a variety of species. But it does require a living cell -- once an animal is dead, all of the cells in its body die almost immediately. The DNA is broken down into smaller and smaller fragments; the amount of time it takes depends on where the cells are preserved. We will never find a living cell, an intact cell, from something that has been dead for a long time like a mammoth.

In some cases, like the bucardo -- this is the ibex that went extinct in the Pyrenees in the early 2000s -- they actually have tissue samples that were taken from the last remaining individual, Celia, before she died. In that case you do have living cells and you can try this process called cloning. It hasn’t been successful yet but it might be in the future. However, I am being a little bit disingenuous, because if we do succeed in bringing mammoth-like traits back to life, we will have to use this process of cloning but we won’t be cloning a mammoth cell. We’ll be cloning an elephant cell, probably an elephant cell that has been edited in some way.

A few weeks ago scientists at Harvard announced that they had taken an elephant cell that was growing in a dish in a lab and, using genome editing technology, swapped out a few places in the genome, where they knew that elephants and mammoths were different, for the mammoth version of those genes. So what they had was an elephant cell that was alive, that was growing in a dish in a lab, that had a little bit of mammoth DNA. Now, we can’t yet clone an elephant because there are some technical challenges involved with the next few processes of cloning. But if we were going to use that to bring these mammoth-like genes or traits back to life, that would be the next step.

So the big question that’s running through my mind -- and I know there are different answers to this -- is just, why? Why devote the resources to trying to bring things back from extinction? 

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Those are two very different questions. I’ll first start with the first one. I think that it’s really important in any one of these cases to start off thinking about this process -- even before we get into really trying to figure out what the technical, ethical and ecological challenges of any particular de-extinction might be -- by having some compelling reason to do it. I think that is absolutely critical.

For the mammoth, if we skip over technical, ethical, ecological problems right now, the answer to the question of why we might want mammoth-like traits back I think is possibly one that’s pretty easy to answer. For example, many of us don’t really want to contemplate a world without elephants, but even elephants are endangered and their habitat is disappearing and they’re being poached and it’s very hard to protect them. The IUCN lists them as an endangered species right now. What if we could use this genome editing technology to make elephants that had a little bit of mammoth-like traits, just enough to allow them to live in colder climates like Europe and North America, maybe even Siberia and Alaska, these high Arctic climates? Could we use this technology as a way to save elephants? I think that is a potentially compelling reason to do this research.

Another reason why that’s been tossed around a bit comes from Sergey Zimov, with the Russian Academy of Sciences, who works up in Cherskii, in northeastern Siberia. He has this place called Pleistocene Park, where he has bison and horses and a bunch of different species of deer. He’s shown that just having these herbivores on the landscape, walking around and turning the soil and recycling nutrients and distributing seeds, has been enough to reestablish this rich resource for herbivores there -- this dense grassland that lives there and allows these animals to flourish. He’s shown that other species like saiga antelopes, that are also endangered, have come to the park now because it’s a great place for them to come and find stuff to eat. So what if having this big herbivore back on the landscape was actually better able to do that, to recreate this rich resource for other species to use, and in a way could be used as a way to conserve biodiversity in the present day? Again, not just elephants, but these other species that lack habitat.

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So compelling reasons to consider bringing extinct species or traits back to life are things like that, not to study mammoths. If we were to bring some animal back that was a hybrid between an elephant and a mammoth -- and it necessarily would be -- this would not be a good way to study mammoths. It wouldn’t be a mammoth, so we wouldn’t learn anything from that. But, to save elephants and reestablish these ecosystems, those are compelling reasons. Now with the mammoth, I think the ethical challenges associated with mammoth de-extinction or cloning elephants are far too great right now to consider this as a realistic option: de-extinction of mammoths or creating elephants with these mammoth-like traits. Elephants don’t fare well in captivity: they tend to become sick, both physically and emotionally. They have trouble reproducing. If they do reproduce, they often injure or even kill their offspring. Until we can figure out how to meet the physical and emotional needs of elephants in captivity, we shouldn’t be using them in any of this kind of research.

The question is different for each of these different animals. So for the passenger pigeon, for example, there are fewer ethical problems probably, because they grow up in eggs rather than inside a mom. But ecologically, I think passenger pigeon de-extinction would be a disaster, because where would we put a billion frickin' birds?

Those giant flocks would be a disaster for air travel.

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What would we do with them? And why, why would we want these birds back? I’m not convinced that there is any particularly compelling reason to bring a passenger pigeon back to life, because it won’t be 100 percent passenger pigeon, so we won’t be able to study its biology, and there’s not really a place that we could put it, to imagine that they might reestablish some missing ecological component that’s been gone since their extinction.

Unless it’s just to make up for the fact that we’re the reason for its extinction...

But I don’t think that’s a good enough reason. We’re the reason for the extinction of a lot of things. If I had to pick, pie in the sky, forget technical, ethical, and ecological challenges, what species that’s extinct that’s our fault that I would like to see back? I would pick the dodo, and that’s because this is the first animal that I ever worked on as a DNA scientist. I wanted to know what kind of bird the dodo was-- this is when I was a PhD student in Alan Cooper’s lab in Oxford. It was great, it was super fun, we answered the question -- it’s a big, fat pigeon -- and it’s just so weird. There are so many different depictions of dodos in our social history, they're kind of a big thing to people, they mean a lot to us and I would love to see one of these things brought back.

But it’s a terrible idea, a terrible idea, because we have not yet solved the problem of why they went extinct. Many people think that they went extinct because we ate them, we hunted them to death. We didn’t. The written accounts of dodos by the Dutch and Portuguese sailors at the time said they tasted terrible. The reason they went extinct was because when we arrived on Mauritius, we brought with us rats, cats, pigs and dogs, stuff like that. Dodos laid a single egg in a nest on the ground, and this made an easy meal for these animals that came with us, like rats. Maybe there are other compelling reasons for dodos. Imagine that from an ecotourism perspective, it might be good for Mauritius, the people of Mauritius, to have this animal there to attract people to come and spend money on the island and invest into the ecology of Mauritius and the people of Mauritius. Until we can find a place on Mauritius where we can release these guys into an environment where there aren’t going to be any rats and cats and pigs and dogs and brown tree snakes or anything else that eats these bird eggs, we shouldn’t do it, because they’ll just go extinct again.

You’re pretty cynical in general about the way the press and the public will react once some of this becomes reality, once we have the first elephant cloned with mammoth genes. How worried are you about the public relations aspect of de-extinction?

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What I’m worried about is that the public will lose even more faith in scientists if they believe that scientists have said that we can clone a mammoth, because we can’t and we’re really not going to be able to. I’m worried that too much hyperbole in this realm is not good for public relationships with scientists and with science. But I’m not worried that we’re having this conversation and that people are mad or that people are excited or people are scared. I think this is all very good. I think that having a conversation about this stuff now, because we can’t do it, is actually a really nice way of bringing this biodiversity crisis that we’re currently in to people’s attention. Most people don’t care about extinctions, as it doesn’t affect them personally. I think the more people that become invested in the idea that we have a problem, that we’re facing a problem, and that might start to care, that’s all good. There’s nothing bad that can come from that.

I would just like to see some of these reports show that just because we can, in a cell in a dish in a lab, change out a few genes, doesn’t mean that we can make a mammoth, that there's a huge gulf between cells growing in a dish in a lab and animals wandering around that look like mammoths. I think that is a danger, that people miss that. That there’s a whole bunch of other technical problems and that in addition to these technical problems there’s an enormous number of ethical and ecological challenges that are just as important that will need to be addressed before we can do this. There’s often this jump from “We can do this one technical thing” to “It’s going to happen.” It’s not that easy.

The other thing I’d imagine people asking is, “If we have this technology, will we be able to bring back the animals that we’re causing to go extinct right now?”

Yeah, and I think bringing them back is not possible because once something is extinct, it’s extinct. But what this technology might be able to do -- and this is where I see the most utility in this kind of technology -- is to help save these animals from going extinct in the first place.

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One of the examples that has been thrown around is black-footed ferrets. Black-footed ferrets are really in danger of extinction, and they’re almost genetically identical to each other because of the really recent population bottleneck. And now there are diseases that are killing them off wherever they remain. But there are preserved remains from black-footed ferrets in museums and there are also preserved tissues, in the Frozen Zoo in San Diego, from animals that died prior to this recent population bottleneck. What if we could use this technology -- and we can’t yet -- but what if we could use this technology to take the immune-related genes in extinct black-footed ferrets, and insert them into living black-footed ferrets, and thereby increase the diversity of the living population to fight disease? Wouldn’t that be cool? Wouldn’t that be a really good use of this exact same technology, but without the ecological problems of introducing a new species, or the ethical problems of using one species to bring back another species?

Yeah, without quite getting into Jurassic Park territory.

Well, Jurassic Park is way off because we can’t get any genetic material from dinosaurs.

Let's talk ethical issues. At the end of the book, you respond to the arguments that people who are very against the concept of de-extinciton have. Are there any worries that people have that you take the most seriously or see the most merit in?

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I take everybody’s worries seriously. I think that all of the fears that people have about de-extinction come from a place of sanity, and we need to have sanity when we’re thinking about this kind of thing. There certainly are enormous ecological risks to reintroducing species or introducing any invasive species into a habitat. Habitats are not static environments and ecosystems don’t stay the same when a species goes extinct. A giant, vacant hole waiting for that species to come back in does not persist. The ecosystem changes, it adapts, other species move in, some other species disappear. If we were to introduce a species into that habitat, whether it's a reintroduction or an invasive species or a hybrid species, it will affect that habitat and the other species in there. We can do thorough risk assessments and evaluate the benefits versus the negative consequences of doing it and come up with what we think is a good plan. But there are always going to be things that we can’t predict.

I think that in some cases it might still be worth taking that risk because we could potentially save a bunch of different species or an entire ecosystem by taking that risk. But there are people who are genuinely worried that we shouldn’t do any sort of hands-on manipulation, and I can very much understand where these fears are coming from. I still think we should at times take these risks, but I’m not discounting that it is a risk. It’s a totally valid concern.


Lindsay Abrams

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