September 23, 2008
Extinct Tortoises Could Be Reborn
An extinct tortoise species could live again, researchers said Tuesday.
Scientists have reported discovering relatives of Geochelone elephantopus alive and thriving.
Cross-breeding the existing tortoises may restore the extinct species, even though it could about a century.
"We might need three or four generations to do this," Gisella Caccone from Yale University told BBC News. "But in theory it could be done, and I think it's pretty exciting to bring back from the dead a genome that we thought was gone."
Of the 15 identified Galapagos species tortoises, four have gone extinct "“ the elephantopus tortoise less than two decades after Charles Darwin first visited the island.
When Darwin visited the Galapagos Islands in 1835, he observed that giant tortoises lived on many of the islands shared many similar features, yet each were different from island to island.
"Thus the several islands of the Galapagos Archipelago are tenanted, as I have elsewhere shown, in a quite marvelous manner, by very closely related species; so that the inhabitants of each separate island, though mostly distinct, are related in an incomparably closer degree to each other than to the inhabitants of any other part of the world," Darwin noted in the On the Origin of Species.
Now, genetic analysts have determined that the Geochelone elephantopus species is close to the Floreana tortoise line.
Several of the Floreana tortoises traveled to Isabela where their genes have combined with the genes of other species.
Discovering the connections be the species is one thing; but using their genetic legacy to revive the extinct Floreana species is another thing.
The Yale researches plan now to conduct a more conclusive examination of the region of Isabela to categorize more tortoises carrying elephantopus genes.
"Then we would have to look at individuals of interest, and genotype them and maybe use marker-assisted selection to help the process along," said Dr Caccone.
However, the extensive gaps in time between generations mean that even if the project is started, it will not be concluding soon. It should take about a century to see the results.
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