Lonesome George is not alone among Galápagos tortoises
Lonesome George has been thought to be the sole survivor of a species of giant Galápagos tortoise (Geochelone abingdoni). However, a multinational team of researchers headed by Yale’s Gisella Caccone and Jeffrey Powell have discovered that this conservation icon may not be alone for much longer.
Lonesome George originates from Pinta, an isolated northerly island of Galápagos, visited only occasionally by scientists and fishermen. In the late 1960s it was noted that the tortoise population on this island had dwindled close to extinction. Indeed, in 1972 only a single male, Lonesome George, was found. He was immediately brought into captivity at the Charles Darwin Research Station on the island of Santa Cruz where he is housed with two female tortoises from a species found on the neighboring island of Isabela. After 35 years, Lonesome George remains uninterested in passing on his unique genes and has failed to produce offspring. His status as the “rarest living creature” (Guinness Records) and continuing saga surrounding the search for a mate has positioned Lonesome George as a potent conservation icon, not just for Galápagos, but worldwide.
In the new work, the Yale team studied the evolutionary history of a species of Galápagos tortoise (G. becki) on Isabela Island that was previously known to be genetically mixed. The study analyzed the distribution of genetic variation within two G. becki populations across the nuclear genome relative to a large database including individuals from all extant species of Galápagos tortoises. The nearly extinct G. abingdoni on Pinta was added to the analysis for the first time by way of genetic data collection from six museum specimens, also including Lonesome George. Population genetic analyses revealed one tortoise sampled on Isabela Island is clearly a first generation hybrid between the native tortoises from the islands of Isabela and Pinta. That is, this tortoise has half his genes in common with Lonesome George; unfortunately it is a male. Given that there are well over 2,000 tortoises of G. becki on Isabela Island and a first generation hybrid was detected in a very small subset of the population, there is hope that a more thorough sampling could reveal a genetically pure Pinta tortoise. In the event additional individuals of Pinta ancestry are discovered, a captive breeding and repatriation program may be enacted for species recovery. These findings offer the potential for transforming the legacy of Lonesome George from an enduring symbol of rarity to a conservation success story.
This work has been carried out in collaboration with the Charles Darwin Research Station and the Galapgos National Park. The Yale Institute for Biospheric Studies (YIBS) ECOSAVE Center, The Bay and Paul Foundation, and the National Geographic Society have financially supported financially this research, and the results have been published in the May 15 2007 issue of Current Biology.
The Yale team is now in the process of seeking funds to organize a large sampling campaign on V. Wolf on Isabela to genotype the majority of the tortoises from that population with the scope of finding additional individuals with Pinta genes. These individuals will eventually be brought to the Charles Darwin research Station on the island of Santa Cruz where a breeding program will be started.
Contributions to further the research on Lonesome George can be made by clicking on the logo below and choosing "Other" as the "area" and typing "Lonesome George" as the "Purpose."
