A mammoth undertaking

Can genetic science bring extinct species back to life? And if it can, should we let it?

Published January 3, 2002 11:52PM (EST)

The woolly mammoth had a 3-foot-long penis and 16-foot tusks.

Its skull, which had a gaping cavity for those tusks, may have inspired the myth of the Cyclops, the one-eyed monster. Mammoth bones have been mistaken for unicorn remains.

And just daring to disturb a mammoth's frozen carcass is still thought by Siberian natives to unlock a fatal curse, like messing with an Egyptian pharaoh's tomb.

Even in extinction, the woolly mammoth has more going for it than most living creatures, and some genetics-happy scientists hope that it can be brought back from the dead to dazzle again with its mangy charms.

In his new book "Mammoth: The Resurrection of an Ice Age Giant," Richard Stone, 35, a London-based editor for Science Magazine, goes mammoth hunting in Siberia with the researchers and dreamers who want not only to raise but to revive the Ice Age beast. Stone will go as far as the frozen tundra to get his story, but he turns down an offer of a celebratory bite of freezer-burned mammoth flesh when the woolly corpse has been successfully chiseled from the frigid ground.

Turning a mammoth corpse into a mammoth clone hasn't happened yet, and some scientists doubt that it ever will. But Stone argues the mammoth is just the most high-profile of the extinct and endangered creatures that may make a comeback thanks to cloning. One group of scientists is already attempting to re-create a woolly mammoth habitat circa 10,000 years ago, Jurassic Park-style, in hopes of accommodating the coming herds of clones.

It may be too soon to look forward to the day when animal-rights protesters will rally to rout the Homo sapiens out of their homes in the Berkeley hills so that the saber-tooth cat can once again roam free. But with the Chinese government already working to clone the disappearing panda, can the ethical debate about the resurrection of early human ancestors be far behind?

Stone told Salon how reproductive biology may soon bring back long-lost species.

Do you really think that the woolly mammoth will be brought back from the dead?

I do. We could see a cloned mammoth within a generation, within 20 years. But there'll be human clones before there are mammoth clones, probably in the next five years.

Why is there so much interest in bringing back a mammoth?

It hasn't walked on the earth for 3,700 years. It's not like one of these more recent extinctions where people are familiar with the animal and they may have saved some of the DNA, even fresh tissue frozen in the hopes of cloning it.

Advanced Cell Technology, the company which is famous for having attempted to clone a human embryo, recently announced that they are trying to resurrect the bucardo, a type of goat that recently became extinct in Spain. But it's a goat.

When you talk about the more charismatic extinct species that have been gone longer, like the woolly rhino, the saber-tooth cat, the mammoth is the most likely candidate because it was one of the more common species from that time, so there are just more remains.

So, what's the holdup? Why haven't we seen a mammoth clone yet?

Researchers haven't found an exquisitely preserved mammoth specimen yet. The Jarkov mammoth was a disappointment. There wasn't much of it left. They found another sample this past spring, and there was more flesh there, but it's not clear how much of it had stayed frozen through millennia. They still need to find that very well-preserved specimen.

How do scientists hope to resurrect the mammoth?

Either through cloning or breeding. Right now, the technology won't allow cloning, because a lot of the mammoth DNA that we have is broken. It's well-preserved as far as ancient DNA goes, but it has breaks in it. The technology needs to develop where you can make repairs to DNA and essentially stitch together an entire mammoth genome to clone.

In Siberia, there are remains that had been in the permafrost for 10,000 years. The DNA of the Australian extinct species, like the huia bird, that's much more degraded DNA. The hope in looking for mammoth or woolly rhino DNA is that it's going to have relatively few breaks, so you can surgically repair the DNA sequence.

If the cloning technology isn't there yet, how would breeding work?

The Japanese reproductive biologist Kazufumi Goto wants to breed mammoths by taking mammoth sperm and implanting it in an elephant egg. Sperm tends to survive for decades frozen, with preserved DNA. Human sperm, for instance, kept frozen under the right conditions, scientists think, can last actually forever, for thousands of years.

So, if you could find frozen mammoth sperm, with its DNA intact, you would take the sperm and inject it into an elephant egg.

You would essentially just defrost it?

Essentially, which is what they do routinely now for couples who have trouble conceiving. They take sperm samples and keep them on ice and try to fertilize embryos.

First, you would select for sperm to ensure a female offspring. If you can get fertilization of a mammoth sperm and an elephant egg, it would divide a couple of stages in a test tube; you would implant it in the womb of an elephant and see if it took. Then, you'd have a half mammoth, half elephant. Then, you would breed it with another mammoth sperm, and after three generations, you'd have a 90 percent mammoth.

Assuming they found well-preserved mammoth DNA, then how would cloning work?

Then, you would essentially do what they did to create Dolly, the sheep. You take the mammoth nucleus, which had the DNA in it, and stick into an elephant egg which had its DNA removed, and then you have this mammoth DNA inside this elephant egg as if fertilization had already taken place. You would essentially try to get this cell to start dividing by zapping it with electricity.

If this Dolly procedure worked, from there it becomes the same as the breeding procedure, but if it's born then you have 100 percent mammoth. With Dolly, the sheep, it took many, many, many of these attempts to get a live birth, and presumably that's going to happen with a cloned mammoth as well.

Some mammoth experts object to attempts to bring them back to life. They balk at creating an animal that could only live in a zoo, or creating a single, lonely specimen of a defunct species. Do you think that these ethical concerns will prevent the resurrection of the mammoth?

I think the scientific imperative will carry the day. That's how it was back when the DNA revolution started. There was a lot of opposition to creating transgenic plants and animals, when they take DNA from a species and put it into the genome of a different species.

Are there any efforts to resurrect early humans using the same techniques?

The early humans that you'd probably be interested in, the Cro-Magnon and the Neanderthal, we just haven't found frozen. But there is this Ice Man that was found in the Italian Alps. He's 5,000 years old -- conceivably you could clone him, if they had kept his tissue frozen the whole time that he was extracted from the ice.

But say you found some decent enough DNA, the Ice Man could be brought back -- a 5,000-year-old person! The question is, would it make a difference? Would the intelligence capacity of a human 5,000 years ago be any different from that today? Because you wouldn't just clone this person as he was. He'd be a baby, and he'd grow up and he'd learn. Presumably, you wouldn't put him in a cave and see how he developed. You'd have to give the cloned baby the opportunities that any other child would have.

The Internet. Teletubbies ...

You'd end up having a normal person just like us. Five thousand years is not a long time in human evolution.

How seriously do wildlife biologists and environmentalists take cloning as a way to prevent the extinction of endangered species?

They don't think that it's really viable for protecting populations right now. So little is known about the reproductive biology of many endangered species, cloning is really a long shot for it to work.

But there's a list of species, like the Sumatran rhino, that they have that they would love to try to clone to see if they can supplement dwindling populations. The Chinese government has a panda cloning project, since there are only about 1,000 pandas left in the wild.

Say scientists succeed in bringing a mammoth back, where would it live?

You need a place to put them that would be similar to the habitat that existed 10,000 years ago. There are certain areas that seem to be close to what it was like 10,000 years ago in Northern Siberia. And there's even an attempt to try to re-create a Pleistocene ecosystem in Northern Siberia, called Pleistocene Park.

It's very wet and boggy in Northern Siberia today. It can't sustain huge populations of grazing animals. It could not sustain mammoths today. Mammoths, presumably, if they were like elephants, need to eat 300 pounds of forage a day. So, you couldn't just stick a mammoth in Northern Siberia and expect it to survive. In the last Ice Age, you had dry grasslands, very rich land that could support lots of grazing animals, lots of mammoths, lots of woolly rhinos, lots of steppe bison.

One theory is that these large animals helped to maintain that ecosystem. Russian ecologist Sergei Zimov is working to bring bison to Siberia to a fenced-off section of land called Pleistocene Park. By disturbing the land he thinks they are going to bring back these Ice Age grasses, which are present in Siberia in very sparse populations. The grasses could then reestablish. If you can transform a section of the permafrost, of the tundra, in this way, to grasslands, then you'd have a place for the mammoths if you could bring them back.

Do you think that some governments, like the United States, will try to stop the resurrection of extinct species, as they have with human cloning?

I don't think any of the governments are going to step in and say: "How dare you! Don't clone the woolly mammoth!"

Animal cloning has taken place, and the only regulatory issues that it's triggered have been animal care, in ensuring that the clones are treated with the same standards as any other research animals. I think that would extend to mammoths as well.

One theory about the mammoths' demise is that a mystery "hyperdisease" killed off the last of the species, a kind of super virulent pathogen. Some scientists express concern that bringing the mammoth back would unleash this mammoth-killing Ebola virus. Is a plague of mammothitis being unleashed upon us really something to worry about?

I think it's credible, but judging by past experience, it's a long shot.

In Siberia, there are people who died of smallpox, buried in the permafrost, and these viruses are alive in there, and you don't get researchers or residents dropping from smallpox that thawed from the ice. More realistically, resurrecting a mammoth may create a reservoir for viruses or bacteria that haven't had one since this species died out. The mammoth might have been a host to a very specific disease. It may not affect humans at all, but it might be a disease that could come back in through the mammoths, and perhaps jump again to elephants, which are already endangered themselves.

Besides the remote possibility of some mystery hyperdisease, are there any dangers to cloning mammoths?

Some cloned animals have had problems. They tend to be really big. Some have bad circulation related to the cloning; others have birth defects. There are a lot of unknowns about the medical risks of cloning. And you don't know whether you're going to have a problem until you see the birth, so that's a huge ethical issue with human cloning. That's what has researchers outraged by some of these efforts by scientists to try to clone humans, forging ahead without knowing what the medical risks might be.

But that won't stop mammoth cloning efforts?

No. But the risk of medical problems could be severe in resurrecting an extinct species, because even in a clone you're not going to be using the mitochondrial DNA from the mammoths. That's going to come from the mother's egg from a closely related species.

There's something called genetic imprinting where the mitochondrial DNA and all the other elements in the egg have a major effect on what genes get turned on in the fetus, and you don't know how that process is going to work with mammoths.

You might create these really pathetic, miserable creatures. Talk about a denouement. All the excitement would really be gone. And all this dream of having mammoths roaming the earth would not happen.

By Katharine Mieszkowski

Katharine Mieszkowski is a senior writer for Salon.

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