The evolutionary history of the sinica-group of Macaque monkeys as revealed by mtDNA restriction site analysis

Abstract

We estimated the phylogenetic relationships of mitochondrial DNA haplotypes within the sinica-group of macaques, which includes Macaca sinica, M. radiate, M. thibetana, M. assamensis, and possibly M. arctoides. Some effort was made to detect intraspecific variation by sampling individuals from different parts of the species' range or from different matrilines. In the case of M. assamensis, individuals were sampled from both subspecies ( M. assamensis assamensis and M. assamensis pelops). Total genomic DNA was extracted from blood samples and cut with a battery of 16 restriction endonucleases. A total of 97 restriction sites were mapped for these enzymes in the sinica-group and M. nemestrina, which was used as an outgroup. Phylogenetic trees constructed by both the maximum parsimony method and the neighbor joining method were highly congruent. A bootstrap analysis of the maximum parsimony tree indicated a high degree of confidence to the association of particular haplotypes within the 80% majority rule consensus tree. An exhaustive search of all possible trees also supported this topology, although one haplotype had to be eliminated from this analysis to save computer time. The results were also unaffected by weighting the character state changes in favor of site gains over site losses. The mtDNA phylogeny produced here differs from trees based on morphology and allozymes in three ways: M. sinica and M. radiata sit in two different branches of the tree; the two subspecies of M. assamensis are separated from one another; and M. arctoides consistently fell outside the rest of the sinica-group. We suggest that the biogeographic histories of these species, along with the sorting of mtDNA haplotype lineages is responsible for our observations. These results support those obtained in several other recent studies in ndicating that speciation from a highly polymorphic ancestor can interfere with our attempts to reconstruct the historical pattern of cladogenesis. One way to lessen this problem is to include within-species variation when using mtDNA to reconstruct phylogenies.