The study, published in Current Biology, gives a peek into the evolutionary history of a species of Galpagos tortoise (G. becki) previously known to be genetically mixed on the neighboring island of Isabela. The results were possible only with advances in technology from these researchers that make DNA from ancient or museum specimens useful for genetic analysis.
Population analyses of a large database including individuals from all 11 existing species of Galpagos tortoises was compared to the genetic variation within two of the G. becki populations. DNA data for the nearly extinct G. abingdoni species from Pinta was available for the first time from six museum specimens and from Lonesome George.
There are well over 2,000 tortoises of G. becki living on the neighboring volcanic Isabela Island, which has only two sites accessible from the sea. The research team collected samples from a total of 89 tortoises 29 at one location, 62 on the other side of the island. Because the subset of the population they sampled was so small, the researchers hope that thorough sampling will locate a genetically pure Pinta tortoise.
The authors speculate that, in the event additional individuals of pure Pinta ancestry are discovered, a captive breeding and repatriation program could be set up for species recovery. "It will take a team of about 20 people about three to four weeks to do a first, exhaustive sampling and transmitter-tagging of the tortoises on the volcano," said Caccone. "Then once individuals of interest are found either hybrids with Pinta or pure Pinta animals an equivalent field expedition will have to be mounted to find the animals and bring them in captivity. But, it is a harsh environment with no local resources and funding such an operation will be costly."
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Contact: Janet Rettig Emanuel
janet.emanuel@yale.edu
203-432-2157
Yale University
30-Apr-2007