National Geographic : 2013 Apr
reviving species 41 first developed, it has a way of becoming very cheap very fast. “Maybe some people thought po- lio vaccines were a distraction from iron lungs,” says George Church. “It’s hard in advance to say what’s distraction and what’s salvation.” But what would we be willing to call salva- tion? Even if Church and his colleagues manage to retrofit every passenger pigeon–specific trait into a rock pigeon, would the resulting creature truly be a passenger pigeon or just an engineered curiosity? If Archer and French do produce a single gastric brooding frog—if they haven’t already—does that mean they’ve revived the species? If that frog doesn’t have a mate, then it becomes an amphibian version of Celia, and its species is as good as extinct. Would it be enough to keep a population of the frogs in a lab or per- haps in a zoo, where people could gawk at it? Or would it need to be introduced back into the wild to be truly de-extinct? “The history of putting species back after they’ve gone extinct in the wild is fraught with difficulty,” says conservation biologist Stuart Pimm of Duke University. A huge effort went into restoring the Arabian oryx to the wild, for example. But after the animals were returned to a refuge in central Oman in 1982, almost all were wiped out by poachers. “We had the animals, and we put them back, and the world wasn’t ready,” says Pimm. “Having the species solves only a tiny, tiny part of the problem.” Hunting is not the only threat that would face recovered species. For many, there’s no place left to call home. The Chinese river dolphin became extinct due to pollution and other pressures from the human population on the Yangtze River. Things are just as bad there today. Around the world frogs are getting decimated by a human- spread pathogen called the chytrid fungus. If Australian biologists someday release gastric brooding frogs into their old mountain streams, they could promptly become extinct again. “Without an environment to put re-created species back into, the whole exercise is futile and a gross waste of money,” says Glenn Albrecht, director of the Institute for Social Sustainability at Murdoch University in Australia. Even if de-extinction proved a complete lo- gistical success, the questions would not end. Passenger pigeons might find the rebounding forests of the eastern United States a welcoming home. But wouldn’t that be, in effect, the intro- duction of a genetically engineered organism into the environment? Could passenger pigeons become a reservoir for a virus that might wipe out another bird species? And how would the residents of Chicago, New York, or Washington, D.C., feel about a new pigeon species arriving in their cities, darkening their skies, and covering their streets with snowstorms of dung? De-extinction advocates are pondering these questions, and most believe they need to be re- solved before any major project moves forward. Hank Greely, a leading bioethicist at Stanford University, has taken a keen interest in inves- tigating the ethical and legal implications of de-extinction. And yet for Greely, as for many others, the very fact that science has advanced to the point that such a spectacular feat is possible is a compelling reason to embrace de-extinction, not to shun it. “What intrigues me is just that it’s really cool,” Greely says. “A saber-toothed cat? It would be neat to see one of those.” j “The thing that i always say is, if you don’t try, how would you know that it’s impossible?” Insung Hwang, cloning expert Check out film footage of the last of their kinds, interviews with scientists, and more on our digital editions.