Can An Extinct Species Be Brought Back To Life Through Breeding?

Sep 15, 2017

Is extinction forever? A Yale researcher is asking that question as she works to revive a type of giant tortoise that used to be found in the Galapagos.

If you could travel back hundreds of years -- the Galapagos would have been filled with lots of different types of giant tortoise.

Over the past three centuries though, lots have died. Populations have declined by about 90 percent, and some species have gone totally extinct. Lonesome George, an iconic tortoise who died in 2012, was the last surviving member of his species.

“The same reason why they went extinct -- humans mingling with them -- is also the reason why we still have bits and pieces of their genome preserved,” said Gisella Caccone, a researcher at Yale University.

For years, she's worked with Galapagos tortoises. Caccone said while in the past mariners crushed population numbers by using tortoises for food and oil, they unknowingly created an opportunity to save them.

That’s because sealers, whalers, and buccaneers moved the tortoises -- taking them from one island and dumping them on another creating mixed ancestry hybrids that today, are basically, walking genetic archives of an extinct tortoise from an island called Floreana.

Now Caccone’s theory is that extinct tortoises might be able to come back if mixed ancestry tortoises are bred in a way that brings the genetic characteristics of extinct species more to the fore.

“Conservation is a science of sub-optimal choices and tortoises need to be on Floreana now,” Caccone said. “Because the island needs the tortoises to regain the ecological equilibriums that were lost when this animal disappeared.”

Any revival would take centuries, and a pure Floreana tortoise might never happen, but Caccone said revitalization and breeding she’s planning now will help the island’s ecology -- for instance by reining in out-of-control vegetation in parts of the Galapagos.