Genome Engineering

Chelonoidis elephantopus, one of the species of Galápagos tortoises that helped Charles Darwin chisel out his theory of evolution, was thought to have become extinct not long after Charles Darwin’s 1835 voyage to the Galápagos Islands. But according to genetic research published in Current Biology, it may live on.

Chelonoidis elephantopus originally lived on Floreana Island. The researchers looked at samples of Chelonoidis becki tortoises from Volcano Wolf, a peak on Isabela Island, and found a number of them carried genes from at least 38 examples of Chelonoidis elephantopus, with some having genetic patterns that could only come from having a purebred Chelonoidis elephantopus as one parent.

“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,” said former Yale postdoctoral researcher Ryan Garrick, now assistant professor at the University of Mississipi and first author of the paper.

Tortoises were often carried in ships in the 1800s, as they were a source of food and oil, and could live for long periods without food and water, and could have been thrown overboard and floated between islands. Although no purebred individuals have been found, around 30 of the hybrids were only around 15 years old, and according to the researchers, these genetic footprints seen in tortoises, which can live for over a hundred years, could suggest that Chelonoidis elephantopus is alive and well and just in hiding, and a captive breeding program could resurrect the species. Though, as the Nature blog cites, is this just going to be too costly?

Garrick, R., Benavides, E., Russello, M., Gibbs, J., Poulakakis, N., Dion, K., Hyseni, C., Kajdacsi, B., Márquez, L., Bahan, S., Ciofi, C., Tapia, W., & Caccone, A. (2012). Genetic rediscovery of an ‘extinct’ Galápagos giant tortoise species Current Biology, 22 (1) DOI: 10.1016/j.cub.2011.12.004