Hybrid origin of a primate, the gray snub-nosed monkey.

Abstract

Hybridization is widely recognized as promoting both species and phenotypic diversity. However, its role in mammalian evolution is rarely examined. We report historical hybridization among a group of snub-nosed monkeys (<i>Rhinopithecus</i>) that resulted in the origin of a hybrid species. The geographically isolated gray snub-nosed monkey <i>Rhinopithecus brelichi</i> shows a stable mixed genomic ancestry derived from the golden snub-nosed monkey (<i>Rhinopithecus roxellana</i>) and the ancestor of black-white (<i>Rhinopithecus bieti</i>) and black snub-nosed monkeys (<i>Rhinopithecus strykeri</i>). We further identified key genes derived from the parental lineages, respectively, that may have contributed to the mosaic coat coloration of <i>R. brelichi</i>, which likely promoted premating reproductive isolation of the hybrid from parental lineages. Our study highlights the underappreciated role of hybridization in generating species and phenotypic diversity in mammals.