Unparalleled Rapid Evolution of Genes in Rhesus and Cynomolgus Macaque Populations.

The killer cell Ig-like receptors (KIR) modulate immune responses through interactions with MHC class I molecules. The region in large cohorts of rhesus and cynomolgus macaque populations were characterized, and the experimental design enabled the definition of a considerable number of alleles ( = 576) and haplotypes, which are highly variable with regard to architecture. Although high levels of polymorphism were recorded, only a few alleles are shared between species and populations. The rapid evolution of allelic polymorphism, accumulated by point mutations, was further confirmed by the emergence of a novel allele in a rhesus macaque family. In addition to allelic variation, abundant orthologous and species-specific genes were identified, the latter of which are frequently generated by fusion events. The concerted action of both genetic mechanisms, in combination with differential selective pressures at the population level, resulted in the unparalleled rapid evolution of the gene region in two closely related macaque species. The variation of the gene repertoire at the species and population level might have an impact on the outcome of preclinical studies with macaque models.