Genetic rediscovery of an ‘extinct’ Galápagos giant tortoise species

Genes from recently extinct species can live on in the genomes of extant individuals of mixed ancestry. Recently, genetic signatures of the giant Galápagos tortoise once endemic to Floreana Island (Chelonoidis elephantopus) were detected within eleven hybrid individuals of otherwise pure Chelonoidis becki on Volcano Wolf, Isabela Island. In this study, we were able to identify hybrid tortoises as well as determine the most likely parental cross that generated them. This is the first rediscovery of a species by way of tracking the genetic footprints left in the genomes of its hybrid offspring.