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Planet Earth

The Frozen Zoo


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While others try to save endangered species in the field, Duane Kraemer has set his sights on the icebox. Kraemer, a professor of veterinary physiology at Texas A&M; University, is leading Project Noah's Ark, a radical effort to deep-freeze genetic material from 2,000 species that may soon go extinct.

Someday vanished animals could be cloned back into existence, to rebuild wild populations or to alleviate inbreeding in captivity. Often, much of the genetic diversity is already gone. Only 1,000 pandas survive, for example. "It would be difficult, but extremely important, to get cells from at least 200 pandas before they go extinct," Kraemer says.

There is also the problem of figuring out how to turn a bottle of cells into a whole panda. Chinese researchers recently made a major advance in that direction when they took cell nuclei from the deceased panda Rong Rong, injected them into rabbit eggs, and grew a panda embryo. The next step is to implant an embryo into a surrogate mother that can carry it to term, a much harder task.

Critics worry that cloning efforts decrease the incentive to protect threatened ecosystems, such as China's bamboo forests. Kraemer sees them instead as a safety net: "It would be tragic if we couldn't preserve their habitats, but it's better to have the animals in managed habitats than not to have them at all."

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