Scientists play 'Jurassic Park' with mammoths

Science

By , Special to The Christian Science Monitor

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.

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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. At one time, they roamed Africa, Asia, Europe, and the Americas.

But history and evolution turned against the woolly mammoths. As the earth warmed up 15,000 years ago, much of their natural habitat disappeared, along with traditional food sources. Paleontologists also theorize that a mysterious pathogen wiped out many mammoths.

Perhaps the most crushing blow, though, came from man. In 10,000 BC, a prehistoric group of nomadic human hunters called the Clovis began to hunt woolly mammoths in Siberia and the Americas as a source of food.

Although no mammoths are alive, they are still very much a part of life in the taiga and others parts of the world.

Ivory from nine-foot-long mammoth tusks is traded in Africa and Asia. In the frozen tundra of Russia, the native Dolgans and other indigenous peoples use ivory to fashion buttons, fish hooks, and other implements.

"They are the symbol of the Ice Age," says Agenbroad, a paleontologist at Northern Arizona University in Flagstaff. "They are depicted in cave art and effigy images. Most of the [Dolgan] reindeer harnesses are held together with ivory buttons. So mammoths are still very much with us, so to speak."

To the frozen north

While mammoth bones and fossils have been found in hundreds of places worldwide - Agenbroad has even found mammoth dung - only in the frozen hinterlands have mammoth bodies emerged relatively intact.

Such was the case when a Dolgan family located twin mammoth tusks protruding from the permafrost near the city of Khatanga in 1997. When they cut off the tusks and took them to a local market to sell, they encountered Bernard Buigues, a French polar explorer and guide.

He persuaded the family to take him to where they had found the tusks. There Mr. Buigues removed the mammoth's head, which was in danger of being exposed to the elements, but left the carcass buried in the permafrost.

Using carbon-dating techniques, scientists determined that the mammoth was a 47-year-old male that died nearly 20,000 years ago, probably after becoming trapped in a muddy swamp and getting frozen over.

Buigues then set about organizing a second expedition, this time with the goal of removing the remainder of the mammoth's body with the explicit hope of recovering DNA. Last month, Buigues - with his team of international scientists and funding from the Discovery Channel - arrived with power tools, generators, and heavy equipment.

The plan was to carve a trench around the mammoth, drill holes through the permafrost beneath the mammoth, slide iron bars through the holes, and then hoist the 25-ton block of ice out with a helicopter. The ice, with mammoth inside, would would be preserved in a permafrost cave.

So far Buigues and his team have completed the excavation and drilled the holes, but winter is rapidly approaching, and they are hoping a shipment of helicopter fuel arrives before the river freezes. Operations in winter are difficult, and warm temperatures in spring could mean disaster.

"If we get a warming and you thaw this block, you could have the entire top layer containing the mammoth start to slough off," says Agenbroad. "Unless we get it into a safe house, it has all the possibilities of further damage."

(c) Copyright 1999. The Christian Science Publishing Society

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