Scientists Play 'Jurassic Park' with Mammoths ; Science

Article excerpt

In the frozen vastness of the Siberian taiga just below the Arctic Circle, the loud chatter of jackhammers and generators crackles through biting sub-zero air.

At this cold, dark outpost on the edge of the world, a team of scientists is prospecting not for gold or precious gems but rather for a treasure from the Ice Age, an intact body of a woolly mammoth encased in a block of ice.

From its frozen body, researchers hope to extract invaluable insights about the flora and fauna of a bygone era. More important, though, they hope to find DNA suitable for cloning - to be used to revive an extinct species.

It's a groundbreaking test of the basic theory laid out in the film "Jurassic Park," and, if successful, it could lead to the revival of many extinct species frozen in Siberian ice.

Much remains to be done. The science of cloning remains extremely difficult, and the Siberian winter could destroy the work accomplished so far. Yet many scientists are already questioning the project's ethical implications, wondering whether humans should undo nature's work.

"Some people think it shouldn't be done, that it goes against nature. But mammoths lasted in the Siberian Arctic until 37,000 years ago. At least one theory is that humans made them become extinct," says Larry Agenbroad, a mammoth expert who is participating in the expedition. "It would be kind of nice to see if we can revive them."

Dr. Agenbroad says many species can attribute their extinction at least in part to the rise of homo sapiens, and therefore it is partly our responsibility to assist in their revival, if possible. "We have records of how the last two dodo birds were killed by humans," he says, adding that modern-day mammoths would not likely multiply to reach past populations or to cause any major environmental hazards.

But there are serious scientific problems to overcome before such possibilities can even be considered. First, scientists need to remove intact DNA from flesh, soft tissue, or possibly sperm cells of the Siberian mammoth. The project could then hinge on how well the DNA is preserved.

"Was the mammoth frozen quickly enough and deeply enough to ensure that little damage was done to the DNA?" asks Karl Flessa, a paleontologist at the University of Arizona in Tucson. "Degraded DNA or DNA with freezer burn is not likely to be of much use."

How to clone a mammoth

Even with intact DNA, however, cloning the mammoth is far from a sure thing. Scientists would have to strip the DNA from an egg cell of an Asian elephant, the closest living relative to a woolly mammoth. The mammoth DNA would then be injected into this egg cell, a technique similar to that used to clone mice. But no one has cloned an elephant, let alone a woolly mammoth. Furthermore, cloning male mammals has proven difficult.

In addition, elephants are scarce, expensive to keep, and at times dangerous to handle. "It's a very inconvenient animal to study because of its size, when you compare that to mice where you can keep thousands at a university facility," says Jonathan Hill, a cloning expert at Texas A&M University. "Little work has been done with elephant eggs."

In their day, mammoths were the largest land mammals on the planet, weighing more than 10 tons and standing 12 feet or taller. They first appeared between 3 million and 4 million years ago in sub- Saharan Africa. …