Indian People - Genetics

Genetics

Basu et al. (2006) emphasize that the combined results from mtDNA, Y-chromosome and autosomal markers suggest 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 northwest; (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 possibly widespread throughout India before the arrival of the Indo-European-speaking nomads, but retreated to southern India to avoid dominance; (7) formation of populations by fission that resulted in founder and drift effects have left their imprints on the genetic structures of contemporary populations; (8) the upper castes show closer genetic affinities with Central Asian populations, although those of southern India are more distant than those of northern India; (9) historical gene flow into India has contributed to a considerable obliteration of genetic histories of contemporary populations so that there is at present no clear congruence of genetic and geographical or sociocultural affinities."

Modern anthropologists classify Indians as belonging to one of four major ethno-racial groups, which overlap significantly because of racial admixture: Caucasoids, Australoids, Mongoloids and Negritos. The Caucasoids are largely confined to the north and generally speak Indo-Aryan languages; Australoids are found in the south and generally speak Dravidian languages; Mongoloids are largely confined to the Northeastern region of the country and for the most part, speak Tibeto-Burman languages; and Negritos are found on the Andaman Islands located on the southeastern side of the country. These speak a language known simply as Great Andamanese, a linguistic isolate not related to any known language. And finally, Austro-Asiatic languages are spoken by only tribals or Adivasis, who can be of either Australoid or Mongoloid racial stock.

According to a major 2009 study published by Reich et al. using over 500,000 biallelic autosomal markers, the modern Indian population is composed of two genetically divergent and heterogeneous populations which mixed in ancient times (about 1,200–3,500 BC), known as Ancestral North Indians (ANI) and Ancestral South Indians (ASI). ASI corresponds to the Dravidian-speaking population of southern India, whereas ANI corresponds to the Indo-Aryan-speaking population of northern India.