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Science in Mind

Scientists debate bringing extinct species back to life

Billions of passenger pigeons once populated the skies of the eastern part of North America. The last one, Martha, died at the Cincinnati Zoo in 1914. Geneticists now think they may be able to resurrect the species.

Robb Kendrick/National Geographic

Billions of passenger pigeons once populated the skies of the eastern part of North America. The last one, Martha, died at the Cincinnati Zoo in 1914. Geneticists now think they may be able to resurrect the species.

It sounds like a scene from “Jurassic Park’’: Molecular biologists, ornithologists, and a bioethicist came together at a meeting at Harvard Medical School in February 2012 to discuss bringing back the passenger pigeon.

The once-abundant bird was driven into extinction by hunters in 1914. The scientists gathered in Boston, convened by environmentalist Stewart Brand and genome entrepreneur Ryan Phelan, were discussing the technologies they might use to revive the species, and whether such a conservation feat could and should be done.

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On Friday, that discussion was aired for a national audience, at a TedX conference convened around the concept of “Deextinction.” It is also the cover story in the April issue of National Geographic.

I spoke with two of the scientists involved in that initial meeting — George Church, the Harvard Medical School geneticist who has developed increasingly sophisticated ways to edit the genome; and Scott V. Edwards, a professor of organismic and evolutionary biology at Harvard University — to get a perspective on the ideas that shaped the conference.

Church said he was tapped for his expertise in technology. He described to the group new tools, many developed in his laboratory, that allowed scientists to very precisely change individual spots in the genome. Such tools made it feasible, Church told them, to take one species and tweak its DNA in the appropriate ways to create a closely related one that might be extinct.

Edwards provided an ornithological perspective. The band-tailed pigeon, a close relative of the passenger pigeon found on the coast of California and in the foothills, would probably be a good starting place if such an endeavor were to move forward.

That’s not to say scientists were in wholehearted agreement that they should start such a project, or that the passenger pigeon was the best candidate.

Church said he likes useful things more than iconic demonstrations. He hasn’t signed up for reviving any species, but he is personally a bit more intrigued by the idea of bringing back mammoths. That interest was sparked in part by a paper published in the journal Science in 2005 that suggests that the “mammoth ecosystem” — in which large herbivores maintained a certain balance of plant life in the Arctic tundra — helped keep the greenhouse gases that fuel global warming in the ground and out of the atmosphere. “I’m always looking for a practical application,” he said.

Edwards said his concern is that if species revival technology became available, it would detract attention and resources from the critical job of protecting habitat and saving existing species.

“It’s a lot of complex questions as to whether it’s a good or bad thing,” Edwards said. “People might say humans need to be more cognizant of our actions and we can’t be constantly correcting our rampant destruction of the environment with these quick-fix technologies.”

Only time will tell which efforts, if any, move forward. But wonder what that future might look like? John James Audubon described the passenger pigeon vividly in his book, “Birds of America”:

“The air was literally filled with Pigeons; the light of noon-day was obscured as by an eclipse, the dung fell in spots, not unlike melting flakes of snow; and the continued buzz of wings had a tendency to lull my senses to repose.”

Carolyn Y. Johnson can be reached at cjohnson@globe.com. Follow her on Twitter @carolynyjohnson.
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