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Science/Tech See other Science/Tech Articles Title: A Real-Life Jurassic Park By resurrecting the woolly mammoth and other species, scientists want to restore nature's balance. Newsweek International Jan. 30, 2006 issue - For the first 3.5 million years or so, woolly mammoths had it pretty easy. Standing more than three meters tall and weighing seven tons, they dwarfed the rest of the animal kingdom. That allowed them to graze or gambol or make more woolly mammoths without any predators to worry about. Then their luck began to sour about 20,000 years ago. Humans showed up in the Eurasian plain and, a few millenniums later, in North America, wielding high-tech weapons of carved bone and stone. Soon the regal Elephantidae were on the run from Siberia to Saskatchewan. Most scholars now agree that hunters—more than climate change or a mystery epidemic—are what doomed the mammoths. Whatever the cause, by 11,000 years ago the king of the Pleistocene was a goner. Or so it seemed. If a group of devotees has its way, this shaggy ice-age mascot—and a host of other bygone megafauna besides—may yet walk again. Last month, writing in the journal Science, zoologist Alexei Tikhonov of the Russian Academy of Sciences and Ross MacPhee of the American Museum of Natural History announced that they had decoded 13 million base pairs of DNA extracted from the jawbone of a frozen mammoth that died 28,000 years ago on the Siberian steppe. The scientists, in other words, had managed to assemble half the woolly-mammoth genome; they claimed that in three years they could finish the job. That would put scientists within striking distance of an even greater feat: repopulating the earth with creatures that vanished ages ago. Genetic wizards have already cloned sheep, monkeys, pigs and cats. But resurrecting millennial beasts like the mammoth or giant armadillo is far trickier. Although many experts scoff at the idea of using science to "restart evolution" through cloning extinct animals, the prospect has sent waves of excitement through biotech labs around the world. "This is the greatest symbol of the Pleistocene era," says Larry Agenbroad, a woolly-mammoth expert at the University of Northern Arizona. For all its charisma, the mammoth is just part of a grand new strategy to restore long-gone megafauna. Scientists call it rewilding. The idea goes hand in hand with new thinking about the relationship between humans and nature—namely, that even the earliest civilizations had what we might think of as an unnatural impact on the natural world around them. Some scientists estimate that the early hunters of the Pleistocene killed off the mammoths and scores of other giant mammals in the Americas in roughly 20 generations—a tick on the evolutionary clock. "When our species goes into a Garden of Eden, things change," says veteran U.S. paleoecologist Paul S. Martin, who pioneered the idea of hunter "overkill" four decades ago. The strategy calls for repopulating the earth with bygone or endangered species as the best way to repair an environment that is out of kilter, and to prevent even more animals from dying out. Proponents hope advances in genetic engineering, including cloning and hybrid breeding, could finally allow their dream to come true. One research team is already trying to bring back the bucardo, a Spanish goat that disappeared five years ago, and an Australian team is studying a way to clone the extinct Tasmanian tiger. In Ireland, where some 9,000 bird species have been lost, scientists are considering reintroducing flightless rails, which are heading for extinction worldwide. Perhaps the most ambitious effort is underway in Siberia, where scientists led by Sergey Zimov are trying to transform a vast swath (16,000 square kilometers) of chilly marshlands in the Yukutia region into the grasslands and dry forests that flourished during the last ice age. Then they plan to let loose long-absent musk oxen, aurochs, elk, wolves and one day maybe even the resurrected woolly mammoth. Zimov calls this Pleistocene Park. Bringing back the ghosts of the Pleistocene would be rewilding's biggest prize but also its biggest challenge. Since DNA falls apart over time, even in the deep freeze of Russia's permafrost, some scientists despair of ever finding enough unbroken mammoth cells to produce a clone. Sperm cells are hardier, and if mammoth semen could be retrieved from the tundra it could be used to impregnate a female elephant (her offspring would be half-breeds). With the mammoth genome at hand, geneticists now speak of creating a transgenic mammoth by removing the nucleus of an egg from, say, an elephant and replacing it with mammoth DNA. Herds of skeptics abound, not least those who object on safety grounds. Would resurrected species trample the suburbs? Rewilding experts say animals would be contained in national parks. Would they bring new viruses? The risk is small but can't be discounted. The notion of reshaping the wilderness may face an uphill climb to public acceptance. In the end, there may be little choice. By failing to intervene, scientists say, we could be unwittingly giving a hand to evolution's hardiest predators: weeds and pests. "Nowhere is pristine anymore," says Cornell University ecologist Joshua Donlan, one of rewilding's leading architects. "In the future, almost every eco-system everywhere is going to be managed. Either we do it by design or default." Rewilding may not resurrect a storybook lost world. But it may help us reimagine the future.
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