High mitochondrial DNA diversity with little structure within and among leaf monkey populations (Trachypithecus cristatus and Trachypithecus auratus)

We used analyses of mitochondrial DNA restriction site polymorphisms to estimate population genetic structure and phylogenetic relationships among 42 individuals from two Asian leaf monkey species (Trachypithecus auratus and T. cristatus) and to compare them to the geographically proximate species, Presbytis comata. We amplified a 2300-base pair fragment spanning the mitochondrial NADH 3 and NADH 4 genes, including their tRNA flanking subunits, glycine and leucine, and digested it with a battery of 22 restriction endonucleases, yielding 21 unique multienzyme haplotypes and 60 variable restriction sites. Presbytis comata is clearly divergent from both Trachypithecus species. Within the Javan T. auratus, our analysis does not support the distinction of two subspecies currently recognized on the basis of morphological features (Weitzel and Groves, 1985). T. auratus and T. cristatus are not internally monophyletic with respect to each other in our phylogenetic analysis. These results indicate either a recent speciation event with the retention of ancestral polymorphisms or that the two taxa are not separate species. Therefore with respect to conserving genetic diversity within the leaf monkey, we would have to consider T. auratus and T. cristatus as essentially one large polymorphic, conservation unit. However, within that conservation unit, T. auratus of Java represent a separate management unit from T. auratus/T. cristatus of Sumatra and Peninsular Malaysia.