A new DNA study of the passenger pigeon brings up an interesting question: Could we bring the species back from extinction?
Genetic engineering now makes it possible to transfer genes across species boundaries. Using these techniques a group named Revive and Restore is working to modify the genes of the passenger pigeon’s closest living relative, the band-tailed pigeon (Patagioenas fasciata), to make a new bird that resembles a passenger pigeon.
If successful, they’ll release the new bird in the wild to repopulate eastern North America.
But a new study published this month in Science may throw a wrench in their plan.
Researchers gathered DNA from the toepads of passenger pigeon museum specimens and sequenced the full genomes of four birds. In doing so they discovered that passenger pigeons were extremely diverse at the ends of their chromosomes but had low diversity in the middle. Most animals, including the band-tailed pigeon, aren’t like that. Most animals are diverse all the way through.
This trait may indicate that the passenger pigeon in its final form had evolved to live in enormous flocks.
So, why did this superspecies die out? Shapiro thinks it’s because the bird specifically evolved to live in mega-flocks, and developed adaptations that became costly when their numbers suddenly shrank at human hands. “Maybe they were simply not adapted to being in a small population, and didn’t have time to recover,” she says. Maybe they hit a tipping point when there were just too few of them to survive, regardless of whether they were being hunted.
Would a small population of passenger pigeons be possible in the wild? And could the birds survive in this century’s altered and deforested landscape? Revive and Restore believes the answer is yes.
Can humans bring back the passenger pigeon? Should we try?
Read more in The Atlantic at: What DNA Says About the Extinction of America’s Most Common Bird … and its possible resurrection.
(photo credits: Passenger pigeon specimens at Carnegie Museum of Natural History by Kate St. John. Band-tailed pigeon from Wikimedia Commons; click on the image to see the original)