A genomic perspective timely needed for re-evaluating the species delimitations, evolutionary trajectories, and conservation strategies of the Galapagos giant tortoises

Abstract

Genome-wide data obtained from even a small number of individuals can provide unprecedented levels of detail about the evolutionary history of populations and species [1], determinants of genetic diversity [2], species boundaries and the process of speciation itself [3]. Loire and Galtier [4] present a clear example, using the emblematic Galápagos giant tortoise (Chelonoidis nigra), of how multi-species comparative population genomic approaches can provide valuable insights about population structure and species delimitation even when sample sizes are limited but the number of loci is large and distributed across the genome.

Ancient mitogenomics elucidates diversity of extinct West Indian tortoises

“…2 , 3 ; Table S6 ), the shallow mitochondrial divergences of the tortoise radiations on the Bahamas and the Galápagos Islands suggest that each archipelago harboured only one species and that the many taxa currently regarded as distinct species 1 , 35 should be returned to subspecies status. This also is in agreement with the weak nuclear genomic divergence of Galápagos tortoises 57 , 58 .…”