(The recent cloning of frozen mice is not applicable to woolly mammoths, Schuster believes, because whereas mice are small and therefore freeze quickly, a mammoth carcass would take many days to ice over—a delay that would likely cause too much DNA degradation for cloning.)
In the nearer term, biologists are hoping to glean insights into such mysteries as how woolly mammoths were adapted to their frigid world and what factors led to their demise. Miller notes that by studying the genomes of multiple mammoths from different time periods, researchers will be able to chart the decrease in genetic diversity as the species died out. The downfall of the mammoths and other species may contain lessons for modern fauna in danger of disappearing, he says.
Indeed, the team is now sequencing DNA they have obtained from a thylacine, an Australian marsupial that went extinct in 1936, possibly as a result of infection. They want to compare its DNA with that of the closely related Tasmanian devil, which is currently under threat from a devastating facial cancer.
“We’re hoping to learn why one species went extinct and the other didn’t and then use that [knowledge] in conservation efforts,” Miller says. If the research turns up genes associated with survival, scientists can use that information to develop a breeding program for the Tasmanian devil that maximizes the genetic diversity of the population—and increases the frequency of genes that confer immunity. Perhaps the greatest promise of ancient DNA is not raising the dead but preserving the living.