Ancient Hybridization with Unknown Population Facilitated High Altitude Adaptation of Canids
60 Pages Posted: 20 Sep 2019 Publication Status: Review CompleteMore...
Genetic introgression provides material for adaptive evolution, but also confounds our understanding of evolutionary history. This is particularly true for canids, a species complex including dogs, wolves, coyotes, jackals, and other wolf-like carnivores, in which genomic analyses have revealed a complex history of admixture and introgression. Among the most enigmatic canid lineages whose origin and evolutionary relationships remain unresolved are the high-altitude wolves of the Tibetan Plateau, the Tibetan grey wolf and the Himalayan wolf. Here, we use newly assembled genomes of high-altitude Tibetan and Himalayan wolves to explore the evolutionary history and adaptation of this charismatic group. We find that Tibetan and Himalayan wolves are closely related to each other, and that as much as 38-43% of their nuclear genome is derived from an as-yet unrecognized wolf-like lineage that is deeply diverged from living Holarctic wolves and dogs. The EPAS1 haplotype, which is present at high frequencies in Tibetan dog breeds and wolves and confers an adaptive advantage to animals living at high altitudes, was probably derived from this ancient lineage. Our study underscores the complexity of canid evolution and demonstrates how admixture and introgression shape the evolutionary trajectories and adaptation of species.
Keywords: hybridization, adaptive evolution, evolutionary history, canid, introgression
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