Mitochondrial DNA analysis reveals diverse histories of tribal populations from India

Abstract

We analyzed 370 bp of the first hypervariable region of the mitochondrial DNA (mtDNA) control region in 752 individuals from 17 tribal and four nontribal groups from the Indian subcontinent, to address questions concerning the origins, genetic structure and relationships of these groups. Southern Indian tribes showed reduced diversity and large genetic distances, both among themselves and when compared with other groups, and no signal of prehistoric demographic expansions. These results probably reflect enhanced genetic drift because of small population sizes and/or bottlenecks in these groups. By contrast, northern groups exhibited more diversity and signals of prehistoric demographic expansions. Phylogenetic analyses revealed that southern and northern groups (except northeastern ones) have related mtDNA sequences albeit at different frequencies, further supporting the larger impact of drift on the genetic structure of southern groups. The Indian mtDNA gene pool appears to be more closely related to the east Eurasian gene pool (including central, east and southeast Asian populations) than the west Eurasian one (including European and Caucasian populations). Within India, northeastern tribes are quite distinct from other groups; they are more closely related to east Asians than to other Indians. This is consistent with linguistic evidence in that these populations speak Tibeto-Burman languages of east Asian origin. Otherwise, analyses of molecular variance suggested that caste and tribal groups are genetically similar with respect to mtDNA variation.

A prehistory of Indian Y chromosomes: Evaluating demic diffusion scenarios

“…27. This scenario would be consistent with a more recent migration event or the continued movement of women into India through the maintenance of social links.…”

The Indian origin of paternal haplogroup R1a1* substantiates the autochthonous origin of Brahmins and the caste system

“…11 The co-existence of IE tribes and DR castes indicates a complex historical interaction and suggests no 'one to one correlation' between language and this social organization. 12 In spite of the consensus on the relatively uniform maternal gene pool of Indian populations and the large efforts through many philological, 13,14 archaeological 15,16 and recent molecular genetic approaches to elucidate rival models, 6,7,9,11,12,[17][18][19][20][21] the history and concepts of the origin of the caste system are still controversial and unclear. The competing main models (the first of them based on shared IE languages) suggest that contemporary Hindu Indians are descendants of primarily West Eurasians who migrated from the Near east, Antolia and the Caucasus 3000-8000 years ago, 13,14 which has been supported by the demic diffusion model 1,22 and validated by molecular genetic data.…”

Diverse genetic origin of Indian Muslims: evidence from autosomal STR loci

“…[61][62][63][64][65][66] This study throws light on religious grounds for clear understanding of genetic diversity patterns in Indian Muslims. According to historians and anthropologists, the augmentation of Islamic faith in India could be through two discrete ways (i) military invasions that flourished Muslim kingdoms and subsequent migration of mercenaries, businessmen and political emissaries from Middle Eastern countries, Iran and Arabia followed by admixture with the local population; (ii) cultural diffusion as a result of absorption and dominance that resulted in a sizeable population embracing Islam.…”