The genetic heritage of the earliest settlers persists both in Indian tribal and caste populations (original) (raw)
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Ethnic India: A Genomic View, With Special Reference to Peopling and Structure
Genome Research, 2003
We report a comprehensive statistical analysis of data on 58 DNA markers (mitochondrial [mt], Y-chromosomal, and autosomal) and sequence data of the mtHVS1 from a large number of ethnically diverse populations of India. Our results provide genomic evidence that (1) there is an underlying unity of female lineages in India, indicating that the initial number of female settlers may have been small; (2) the tribal and the caste populations are highly differentiated; (3) the Austro-Asiatic tribals are the earliest settlers in India, providing support to one anthropological hypothesis while refuting some others; (4) a major wave of humans entered India through the northeast; (5) the Tibeto-Burman tribals share considerable genetic commonalities with the Austro-Asiatic tribals, supporting the hypothesis that they may have shared a common habitat in southern China, but the two groups of tribals can be differentiated on the basis of Y-chromosomal haplotypes; (6) the Dravidian tribals were po...
Paleoanthropological evidence indicates that modern humans reached South Asia in one of the first dispersals out of Africa, which were later followed by migrations from different parts of the world. The variation of 20 microsatellite and 38 binary polymorphisms on the non-recombining part of the uniparental, hapliod Y-chromosome was examined in 1434 male individual of 87 different populations of India to investigate various hypothesis of migration and peopling of South Asia Sub-continent. This study revealed a total of 24 paternal lineages, of which haplogroups H, R1a1, O2a and R2 portrayed for approximately 70% of the Indian Y-Chromosomes. The high NRY diversity value (0.893) and coalescence age of approx. 45-50 KYA for H and C haplogroups signified an early settlement of the subcontinent by modern humans. Haplogroup frequency and AMOVA results provide similar evidence in support of a common Pleistocene origin of Indian populations, with partial influence of Indo-European gene pool on the Indian society. The differential Y-chromosome and mt DNA pattern in the two Austric speakers of India signaled that an earlier male-mediated exodus from South East Asia largely involved the Austro-Asiatic tribes, while the Tibeto-Burman males migrated with females through two different routes; one from Burma most likely brought the Naga-Kuki-Chin language and O3e Y-chromosomes and the other from Himalayas, which carried the YAP lineages into northern regions of subcontinent. Based on distribution of Y-chromosome haplogroups (H, C, O2a, and R2) and deep coalescing time depths for these paternal lineages, we propose that the present day Dravidian speaking populations of South India are the descendants of earliest Pleistocene settlers while Austro-Asiatic speakers came from SE Asia in a later migration event.
Genetic evidence on the origins of Indian caste populations
Genome …, 2001
The origins and affinities of the ∼1 billion people living on the subcontinent of India have long been contested. This is owing, in part, to the many different waves of immigrants that have influenced the genetic structure of India. In the most recent of these waves, Indo-European-speaking people from West Eurasia entered India from the Northwest and diffused throughout the subcontinent. They purportedly admixed with or displaced indigenous Dravidic-speaking populations. Subsequently they may have established the Hindu caste system and placed themselves primarily in castes of higher rank. To explore the impact of West Eurasians on contemporary Indian caste populations, we compared mtDNA (400 bp of hypervariable region 1 and 14 restriction site polymorphisms) and Y-chromosome (20 biallelic polymorphisms and 5 short tandem repeats) variation in ∼265 males from eight castes of different rank to ∼750 Africans, Asians, Europeans, and other Indians. For maternally inherited mtDNA, each caste is most similar to Asians. However, 20%-30% of Indian mtDNA haplotypes belong to West Eurasian haplogroups, and the frequency of these haplotypes is proportional to caste rank, the highest frequency of West Eurasian haplotypes being found in the upper castes. In contrast, for paternally inherited Y-chromosome variation each caste is more similar to Europeans than to Asians. Moreover, the affinity to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, particularly East Europeans. These findings are consistent with greater West Eurasian male admixture with castes of higher rank. Nevertheless, the mitochondrial genome and the Y chromosome each represents only a single haploid locus and is more susceptible to large stochastic variation, bottlenecks, and selective sweeps. Thus, to increase the power of our analysis, we assayed 40 independent, biparentally inherited autosomal loci (1 LINE-1 and 39 Alu elements) in all of the caste and continental populations (∼600 individuals). Analysis of these data demonstrated that the upper castes have a higher affinity to Europeans than to Asians, and the upper castes are significantly more similar to Europeans than are the lower castes. Collectively, all five datasets show a trend toward upper castes being more similar to Europeans, whereas lower castes are more similar to Asians. We conclude that Indian castes are most likely to be of proto-Asian origin with West Eurasian admixture resulting in rank-related and sex-specific differences in the genetic affinities of castes to Asians and Europeans. Shared Indo-European languages (i.e., Hindi and most European languages) suggested to linguists of the nineteenth and twentieth centuries that contemporary Hindu Indians are descendants of primarily West Eurasians who migrated from Europe, the Near East, Anatolia, and the Caucasus 3000-8000 years ago (Poliakov 1974; Renfrew 1989a,b). These nomadic migrants may
Mitochondrial DNA analysis reveals diverse histories of tribal populations from India
European Journal of Human Genetics, 2003
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.
"L is linked to the Dravidian people and the Elamite as well as Indus Valley culture. L is common in Indians, Iranians, some West Asians, and some Europeans. L corresponds directly to the expansion of the Dravidian people and the IVC.” Human Y chromosome haplogroup L1-M22 traces Neolithic expansion in West Asia and supports the Elamite and Dravidian connection “West and South Asian populations profoundly influenced Eurasian genetic and cultural diversity. We investigate the genetic history of the Y chromosome haplogroup L1-M22, which, while prevalent in these regions, lacks in-depth study. Robust Bayesian analyses of 165 high-coverage Y chromosomes favor a West Asian origin for L1-M22 ∼20,600 years ago. Moreover, this haplogroup parallels the genome-wide genetic ancestry of hunter-gatherers from the Iranian Plateau and the Caucasus. We characterized two L1-M22 harboring population groups during the Early Holocene. One expanded with the West Asian Neolithic transition. The other moved to South Asia ∼8,000-6,000 years ago but showed no expansion. This group likely participated in the spread of Dravidian languages. These South Asian L1-M22 lineages expanded ∼4,000-3,000 years ago, coinciding with the Steppe ancestry introduction. Our findings advance the current understanding of Eurasian historical dynamics, emphasizing L1-M22’s West Asian origin, associated population movements, and possible linguistic impacts.” “Genetic studies suggest that L-M20 may be one of the haplogroups of the original creators of the Indus Valley Civilisation. McElreavy and Quintana-Murci, writing on the Indus Valley Civilisation, state that One Y-chromosome haplogroup (L-M20) has a high mean frequency of 14% in Pakistan and so differs from all other haplogroups in its frequency distribution. L-M20 is also observed, although at lower frequencies, in neighbouring countries, such as India, Tajikistan, Uzbekistan and Russia. Both the frequency distribution and estimated expansion time (~7,000 years ago) of this lineage suggest that its spread in the Indus Valley may be associated with the expansion of local farming groups during the Neolithic period.”
BMC …, 2006
Background: India is a country with enormous social and cultural diversity due to its positioning on the crossroads of many historic and pre-historic human migrations. The hierarchical caste system in the Hindu society dominates the social structure of the Indian populations. The origin of the caste system in India is a matter of debate with many linguists and anthropologists suggesting that it began with the arrival of Indo-European speakers from Central Asia about 3500 years ago. Previous genetic studies based on Indian populations failed to achieve a consensus in this regard. We analysed the Y-chromosome and mitochondrial DNA of three tribal populations of southern India, compared the results with available data from the Indian subcontinent and tried to reconstruct the evolutionary history of Indian caste and tribal populations.