A microsatellite study to disentangle the ambiguity of linguistic, geographic, ethnic and genetic influences on tribes of India to get a better clarity of the antiquity and peopling of South Asia.

An understanding of the genetic affinity and the past history of the tribal populations of India requires the untangling of the confounding influences of language, ethnicity, and geography on the extant diverse tribes. The present study examines the genetic relationship of linguistically (Dravidian, Austro-Asiatic, and Tibeto-Burman) and ethnically (Australian and East Asian) diverse tribal populations (46) inhabiting different regions of the Indian subcontinent. For the purpose, we have utilized the published data on allele frequency of 15 autosomal STR loci of our study on six Adi sub-tribes of Arunachal Pradesh and compared the same with the reported allele frequency data, for nine common autosomal STR loci, of 40 other tribes. Phylogenetic and principal component analyses exhibit geography based clustering of Tibeto-Burman speakers and separation of the Mundari and Mon-Khmer speaking Austro-Asiatic populations. The combined analyses of all 46 populations show clustering of the groups belonging to same ethnicity and inhabiting contiguous geographic regions, irrespective of their different languages. These results help us to reconstruct and understand three plausible scenarios of the antiquity of Indian tribal populations: the Dravidian and Austro-Asiatic (Mundari) tribes were possibly derived from common early settlers; the Tibeto-Burman tribes possibly belonged to a different ancestry and the Mon-Khmer speaking Austro-Asiatic populations share a common ancestry with some of the Tibeto-Burman speakers.