The debate over whether, how, and why to clone extinct animals is louder than ever as scientists inch toward reviving long-extinct species.
Ian Wilmut, a professor at the University of Edinburgh's Center for Regenerative Medicine outlined on July 31 a way to clone a wooly mammoth, 2 months after researchers in Russia unearthed a piece of mammoth containing liquid blood. Wilmut is responsible for cloning Dolly the sheep in the 1990s.
One of the challenges of cloning extinct species is that DNA breaks down over time. Some scientists have ruled out the possibility of cloning dinosaurs due to this fact. However, with relatively recent extinctions, scientists can combine the DNA of the extinct species with that of a close relative.
"That's not making a mammoth. It's 'mammothifying' an elephant."
Cloning a mammoth would require retrieving tissue cells and converting them to stem cells. Also needed are thousands of unfertilized eggs from females of a closely related species (an elephant), says Wilmut, noting that extracting eggs from living elephants is unethical given their slim populations.
Woolly mammoths thrived in North America and Eurasia during the Pleistocene period, which ended about 11,700 years ago, and are thought to have been hunted into extinction by humans of that era.
Leading the race to clone the first woolly mammoth is Hwang Woo-suk, a controversial South Korean cloning expert. Hwang attracted attention when he claimed to have cloned a human being. His findings were later found to be fabricated. Since then Hwang says he's cloned coyotes and will clone a mammoth.
Scientists have successfully cloned a Pyrenean Ibex goat, a species that became extinct in 2000. That proved cloning extinct species from old tissue is possible, even though the Ibex clone survived only 7 minutes. Some are keen on cloning a neanderthal, the genome of which German scientists have sequenced.
"[De-extinction has] gone very much further, very much more rapidly than anyone ever would've imagined. What we really need to think about is why we would want to do this in the first place, to actually bring back a species."
Proponents of de-extinction say the process would stimulate biodiversity and may lead to breakthroughs in everything from biology to medicine. Most species also provide an ecological balance to their habitat that leaves when they die off, although de-extinct animals will likely be held in captivity.
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One organization, known as the Ark Corporation, is working with Revive and Restore on bringing back the passenger pigeon, driven to extinction in 1914 from over-hunting. Ark co-founders say the science of de-extinction has broader implications.
"At this moment, brave conservationists are risking their lives to protect forest elephants from armed poachers. And we're talking in this safe auditorium about bringing back the woolly mammoth?"
Opponents of de-extinction say that the new fascination with the possibility detracts from conservation efforts. Scientists should be focusing on keeping endangered species from becoming extinct, they say.
The University of Illinois held an "ethics of de-extinction" event the evening of Nov. 15. The two-hour conference featured speakers addressing topics such as the "promises and pitfalls" of bringing back recently extinct animals, along with how creatures would react to an altered environment and climate.