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Bringing the dead back to life

UBC scientist tries to bring back extinct tortoise


 

A University of British Columbia geneticist is among a group of international scientists trying to bring back an extinct giant tortoise that disappeared over a century ago. The scientists hope to breed generations of “strange” animals that are a hybrid of the extinct species and another.

Michael Russello, of the Centre for Species at Risk and Habitat Studies at the Okanagan campus of UBC, said the lost tortoises once found on the Galapagos island of Floreana were believed exterminated in the mid-1800s through intense harvesting. He said researchers have extracted DNA samples from specimens of the extinct animals collected by early biologists and stored at the American Museum of Natural History in New York and the Museum of Comparative Zoology at Harvard University in Cambridge, Ma.

By comparing the DNA material from the lost tortoise species, called geochelone elephantopus, to about 30 of tortoises on Galapagos island of Isabela, scientists have learned the two species are genetically related.

Their findings of the scientists, which included Russello and colleagues from Yale University, Australia’s Macquarie University and Italy’s University of Florence, were published this week in the journal Proceedings of the National Academy of Sciences.

Russello said scientists became interested in the Isabela Island tortoises because they just looked so strange.

“They don’t look like they belong there, in that looking at their shell shape, they don’t look like the native tortoise on Isabela,” he said. “Now that we have these museum specimens and we’re able to understand what a Floreana tortoise looked like at the genetic level we’re able to determine that, in fact, half to an even greater percentage of the genome of these aliens, these weirdos on the northern Isabela, are actually hybrids between a Floreana species and the native species on Isabela. So the genetic signature of the Floreana species lives on in this species.”

In December, Russello and a team of about 20 researchers will head out on a three-week expedition to extract genetic material from tortoises at Isabela Island, home to 2,000 of the animals. Russello said scientists will then start a captive-breeding program of Isabela tortoises who share a large percentage of genetic material with the extinct species so successive generations can be bred in the hopes of one day producing a nearly purebred form of the extinct tortoises.

“So we could pick a male that has 70 per cent of its genome that’s shared with the Floreana species and pick a female that has (a high percentage) and breed them.” Russello said the research will be important in preserving other lost species of animals. “The Galapagos tortoise are a flagship species, they’re a flagship for evolutionary theory, a flagship for conservation of biological diversity. So it brings attention to this growing and mounting problem of biological diversity loss.”

-a report from the Canadian Press


 
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