Whole Mitochondrial Genomic and Y-Chromosomal Phylogenies of Burmese Long-Tailed Macaque (Macaca fascicularis aurea) Suggest Ancient Hybridization between fascicularis and sinica Species Groups

Macaca fascicularis aurea (Burmese long-tailed macaque) is 1 of the 10 subspecies of Macaca fascicularis. Despite having few morphological differences from other subspecies, a recent phylogeographic study showed that M. f. aurea is clearly distinct genetically from Macaca fascicularis fascicularis (common long-tailed macaque) and suggests that M. f. aurea experienced a disparate evolutionary pathway versus other subspecies. To construct a detailed evolutionary history of M. f. aurea and its relationships with other macaque species, we performed phylogenetic analyses and divergence time estimation of whole mitochondrial genomes (2 M. f. aurea, 8 M. f. fascicularis, and 16 animals of 12 macaque species) and 2871 bp of the Y chromosome (1 M. f. aurea, 2 M. f. fascicularis, and 5 animals of 5 macaque species) and haplotype network analysis of 758 bp of the Y chromosome (1 M. f. aurea, 2 M. f. fascicularis, and 21 animals of 19 macaque species). Whereas the Y chromosome of M. f. aurea clustered with those of the fascicularis species group in the phylogenetic and haplotype network analyses, its mtDNA clustered within the clade of the sinica species group. Based on this phylogenetic incongruence and the estimated divergence times, we propose that proto-M. f. aurea underwent hybridization with a population of the sinica species group between 2.5 and 0.95 MYA after divergence from the common ancestor of M. fascicularis. Hybridization and introgression might have been central in the evolution of M. f. aurea, similar to what occurred in the evolution of other macaque species and subspecies.