Comparative genomics reveals the hybrid origin of a macaque group.

Abstract

Although species can arise through hybridization, compelling evidence for hybrid speciation has been reported only rarely in animals. Here, we present phylogenomic analyses on genomes from 12 macaque species and show that the <i>fascicularis</i> group originated from an ancient hybridization between the <i>sinica</i> and <i>silenus</i> groups ~3.45 to 3.56 million years ago. The X chromosomes and low-recombination regions exhibited equal contributions from each parental lineage, suggesting that they were less affected by subsequent backcrossing and hence could have played an important role in maintaining hybrid integrity. We identified many reproduction-associated genes that could have contributed to the development of the mixed sexual phenotypes characteristic of the <i>fascicularis</i> group. The phylogeny within the <i>silenus</i> group was also resolved, and functional experimentation confirmed that all extant Western <i>silenus</i> species are susceptible to HIV-1 infection. Our study provides novel insights into macaque evolution and reveals a hybrid speciation event that has occurred only very rarely in primates.