Not all is black and white: phylogeography and population genetics of the endemic blackbuck (Antilope cervicapra)

摘要

Genetic diversity of organisms is an indicator of their long-term survival and can potentially be shaped by the extent of geneflow between populations. Geographical features and anthropogenic interferences can both obstruct and also facilitate animal movement, directly or indirectly. Such patterns have not been extensively studied across grasslands in the Indian subcontinent which is a mosaic of both natural and man-made topography. This study looks at genetic variation in an endemic ungulate, the Antilope cervicapra or blackbuck, throughout its distribution range. Using mitochondrial and nuclear (microsatellite) information, we find that different markers shed light on different aspects of their evolutionary history. Absence of robust geographical clustering in mitochondrial DNA indicate recent isolation in these populations, while lack of shared haplotypes between sampling locations suggests female philopatry. Nuclear data shows the presence of three genetic clusters in this species, pertaining to the Northern, Southern and Eastern regions of India. Our study also shows that an ancestral stock separated into two groups that gave rise to the North and South clusters and the East population was derived from the South at a later time period. Both microsatellite and mitochondrial data indicate that the population from the Eastern part of India is genetically distinct and the species as a whole shows signatures of having undergone recent genetic expansion. In spite of immense losses in grassland habitats across India, blackbucks seem to have well-adapted to human altered landscapes and their numbers are beginning to show an upward trend.