Genetic experiments could bring back extinct animals

Will we ever see a woolly mammoth again? What about the striped Tasmanian tiger, once-prolific passenger pigeon, or the imposing wild cattle called aurochs? Our species has played a role in the extinction of these and many other species. But now some scientists are proposing a radical turn of the tables: Bringing lost species back from the dead. Three main methods for "de-extinction" have been proposed. Cloning gets the most attention, thanks in part to the science fiction of Jurassic Park. We probably won't ever see a Tyrannosaurus—despite the discovery of degraded soft-tissue remnants in fossilized dinosaur bone, no one has ever found non-avian dinosaur DNA—but cloning is plausible for less ancient creatures whose genomes can be reconstructed. And while mammoths tend to hog the spotlight when such proposals are discussed, researchers are also considering resurrecting other species that might not be as famous, but are equally charismatic. Cloning might not be the easiest, or best, route to de-extinction in some cases. If a close relative of a lost species is still alive, researchers can tinker with that genome to "reverse engineer" the extinct species. That's how some ornithologists and geneticists envision bringing back the passenger pigeon. There may be an even simpler way to revive some lost species, such as aurochs, the ancestors of domestic cows. Aurochs survived alongside their domesticated descendants until the early 17th century, when the species ultimately succumbed to disease, habitat loss, and human mismanagement. Now, scientists including Henri Kerkdijk-Otten of the Megafauna Foundation hope to re-create the auroch through a process called "breeding back." Starting with domestic cattle, the process uses strategic mating to incrementally restore the anatomy and the genome of an extinct animal. The advantage of such an approach, Kerkdijk-Otten says, is that it would utilize cattle already adapted to the world's present ecology, rather than trying to re-create an animal from a different time and climate...more