The Evolutionary Genomics Of Pre-Domesticated Horses

Horses have played a critical role in history, revolutionizing warfare and providing new power for exploring the world as well as extra-food resources and precious help for cultivating crops. However, almost all horses are gone in the wild, and the Przewalski horse from Mongolia, which is believed to be the last representative of wild horses, is presently endangered. This limits our ability to infer the long-term evolutionary trajectory of the horse lineage from genomic data of extant individuals. We have used state-of-the-art ancient DNA methods in combination with second and third generation sequencing technologies in order to reconstruct complete genomes of prehistoric horses. Direct comparison to the sequence information present among modern breeds revealed specific evolutionary signatures regarding the demographic, admixture and selective forces that have shaped the horse genome over time. This work illustrates how next-generation sequencing approaches tailored to the specificities of ancient DNA molecules now enable the characterization of whole genomes from non-model organisms, even when minute amounts of genetic material are preserved.