Comparative genomics reveals the hybrid origin of a macaque group

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 fascicularis group originated from an ancient hybridization between the sinica and silenus groups similar to 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 fascicularis group. The phylogeny within the silenus group was also resolved, and functional experimentation confirmed that all extant Western silenus 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.

Automated summary

Through phylogenomic analysis of 12 macaque species, we discovered that the fascicularis group originated from an ancient hybridization event between the sinica and silenus groups around 3.45 to 3.56 million years ago. The X chromosomes and low-recombination regions showed equal contributions from each parental lineage, suggesting their importance in maintaining hybrid integrity. We also identified reproduction-associated genes and confirmed susceptibility to HIV-1 infection in all extant Western silenus species. Our study provides new insights into macaque evolution and highlights a rare hybrid speciation event in primates.