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High Levels of Genetic Divergence across Indian Populations

Posted by PLOS_Genetics on 20 Feb 2008 at 11:31 GMT

Originally submitted as a Reader Response by Clyde Winters (c-winters@govst.edu) on 2 May 2007:

Rosenberg et al. (2006) argue that there is a low level of genetic divergence across geographically and linguistically diverse Indian populations based on their analysis of Indo-Aryan and Dravidian speakers from India.

East and Northeast Indian tribes speak Austro-Asiatic and Tibeto-Burman languages (respectively) [1-2]. The Austro-Asiatic people were probably the original inhabitants of India. Kumar et al. have presented convincing Y-chromosome evidence that Austro-Asiatic people of India and Southeast Asia belonging to the haplogroup O-M95 originated in India, particularly among the Mundari [1-3]. They probably migrated to Southeast Asia 40,000ybp.

The Dravidian and Indo-Aryan people probably belong to the same population and share a Proto-Dravidian MRCA. Due to early Dravidian settlement in Northern India there is a Dravidian substratum in Indo-Aryan [4-5]. There are Dravidian loans in the Rg Veda [6-8], even though Aryan recorders of this work were situated in the Punjab, which was probably occupied around this time by Dravidians [4].

In conclusion, the presence of East Asian and Austro-Asiatic specific mtDNA in India makes it clear that there is extensive genetic divergence across geographically and linguistically diverse Indian populations [1-3]. Moreover, use of Indo-Aryan and Dravidian speakers as representative samples of diverse Indian populations was not an accurate example of the linguistic and geographical diversity of Indian populations because TMRCA of the Indo-Aryan and Dravidian speakers in India was probably a Proto-Dravidian [5].

References
1. Cordaux R, Aunger R, Bentley G, Nasidze I, Sirajuddin SM, et al. (2004) Independent origins of Indian caste and tribal paternal lineages. Curr Biol 14: 231–235.
2. Cordaux R, Saha N, Bentley GR, Aunger R, Sirajuddin SM, et al. (2003) Mitochondrial DNA analysis reveals diverse histories of tribal populations from India. Eur J Hum Genet 11: 253–264.
3. Kumar V, Reddy ANS, Babu JP, et al. (2007). Y-chromosome evidence suggests a common paternal heritage of Austro-Asiatic populations. BMC Evolutionary Biology, 7:47.
4. Winters C (1989). Review on Dr. Asko Parpola’s ‘The Coming of the Aryans’. International Journal of Dravidian Linguistics 18 (2): 98-127.
5. 1988c. The Proto-Dravidians in Central Asia. Journal of Tamil Studies 31: 73-76.
6. Emeneau M and T Burrow. 1962. Dravidian Borrowing from Indo-Aryan. Berkeley: University of California Press.
7. Southworth FC (1977). Lexical evidence for early contacts between Indo-Aryan and Dravidian. Proc. Of the Conf. On Aryan and Non-Aryan in India, 1976. University of Michigan.
8. ISDL. 1983. Report on the Dravidian Languages. International Journal of Dravidian Linguistics 12(1): 227.