Phylogenetic Position of the Genus Trachypithecus as Inferred from Y-chromosome and Autosomal DNA Sequences

We present a molecular study examining the phylogenetic position of the genus Trachypithecus in relation to other Asian colobi ne genera. We used two unlinked nuclear gene regions to estimate the phylogenetic positions among the species classified as Trachypithecus. We sequenced 3100 base pairs of the Y-chromosome TSPY and SRY genes and 1694 base pairs of the autosomal IRBP intron-3 locus from two species of Trachypithecus (T. cristatus and T. obscurus). Other members of Asian colobines were used as the outgroups. Our interpretation based on character and distance analyses suggests that Trachypithecus forms its own monophyletic clade distinct from other Asian colobines. Relative genetic distances and bootstrap support values from two unlinked nuclear regions further confirm the monophyly of Trachypithecus.