January 9, 2012
Scientists Find Offspring of Tortoises Believed Extinct
A giant Galapagos tortoise species believed to have been extinct for 150 years may actually still be alive, researchers from Yale University have discovered.
According to Telegraph Science Correspondent Nick Collins, experts believe that the species in question, Chelonoidis elephantopus, died out shortly after Charles Darwin's visit to the Galapagos Islands in 1835.
However, the researchers say that they have found hybrid tortoises on the island of Isabela "that appear to have C. elephantopus as one of their parents," BBC News Environmental Correspondent Richard Black reported Monday. Some of the hybrids are no more than 15 years old, meaning that the parents are most likely still alive, he added.
"Researchers did DNA testing of 1,600 tortoises on Isabela Island in the Galapagos and found at least 84 animals who were the direct offspring of a different tortoise species from nearby Floreana Island long believed gone," said USA Today's Elizabeth Weise.
"This is some of the most exciting news that I've seen for the Galapagos in a long time," Linda Cayot, science adviser to the Galapagos Conservancy of Fairfax, Virginia, told Weise. "To have a species that was thought to be extinct in the middle of the 1800s come back is amazing."
In a January 9 press release, Yale University representatives said that the research team journeyed to the northern tip of the island in 2008. There, they collected blood samples from the creatures and compared them to a genetic database of both living and extinct tortoise species.
Their analysis unveiled genetic signatures belonging to C. elephantopus in 84 Volcano Wolf tortoises, leading them to conclude that one of their parents had to be "a purebred member of the missing species."
Thirty of those cases involved tortoises sired within the last 15 years, and considering that a tortoise can live for more than a century, the researchers state that there is "a high probability that many purebreds are still alive."
Their findings will appear in the January 10 issue of Current Biology.
"This is not just an academic exercise," Gisella Caccone, a senior research scientist with the university's Department of Ecology and Evolutionary Biology and the senior author of the paper, said in a statement. "If we can find these individuals, we can restore them to their island of origin. This is important as these animals are keystone species playing a crucial role in maintaining the ecological integrity of the island communities."
"To our knowledge, this is the first report of the rediscovery of a species by way of tracking the genetic footprints left in the genomes of its hybrid offspring," added first author Ryan Garrick, formerly of Yale and now an assistant professor at the University of Mississippi. "These findings breathe new life into the conservation prospects for members of this flagship group."
Image Caption: This tortoise is a hybrid of G. Becky and C. elephantopus, a species native to Floreana Island some 200 miles away and thought to be extinct. Genetic analysis of tortoise population on Isabela Island suggests purebred individuals of C. elephantopus must still be alive on Isabela. Credit: Courtesy of Yale University
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