Understanding the Phylogenetics of Indian Hoolock Gibbons: Hoolock hoolock and H. leuconedys

Abstract

Information about the taxonomy and geographical distribution of a species is essential to understand its evolution and for conservation efforts. The phylogeny of the Hylobatidae remains unclear. India is reported to have one species of Hoolock gibbon (Hoolock hoolock) but a recent study based on pelage colour suggested that another species, H. leuconedys, occurs in the Mishmi Hills between the Dibang and Nao Dehing rivers in Arunachal Pradesh. We examined whether H. leuconedys occurs in India and its evolutionary relationships with other Hylobatidae species. We collected blood, tissue, and fecal samples from various populations of H. hoolock (N = 17) and the Mishmi Hills gibbons (N = 14) from their distribution in Northeast India, zoos, and rescues centers. We isolated DNA from these samples and constructed phylogenetic trees using partial D-loop and COI markers. We also performed whole mitochondrial analysis to study the phylogenetics of the Hylobatidae family. Our genetic analysis showed that none of the samples from India were H. leuconedys, and that all samples from the Mishmi Hills could be assigned to H. hoolock. Our mitogenome analysis supported this conclusion. We estimate that gibbon divergence from a common ancestor occurred 8.38 mya and that the split between H. hoolock and H. leuconedys occurred 1.49 mya. These findings will facilitate exchange of individuals from different zoos for captive breeding programs and conservation and management of wild populations of these gibbons.