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Wednesday, November 26, 2008

Elamo-Harappan origins for Haplogroup J2 in India?

The presence of Haplogroup J2 in India, including the subclades M410 and M241 has been an often overlooked clue to the origins of M172. Sengupta et al, in 2005 worked to explain the presence of M172 in India. Their paper provides an immediate acknowledgement of the proposed spread of proto-Elamo-Dravidian speaking peoples into India originating from the Indus Valley and southwest Persia. The idea that M172 may have been carried into India with proto-Elamo-Dravidian groups is supported by the frequencies of Haplogroup J in one of the only remaining Dravidian Speaking ethnic groups in the Iranian Plateau, the Brahui. 28% of the Brahui, an ethnic Dravidian speaking group from Western Pakistan were found to carry the mutation defining Haplogroup J. Overall Haplogroup J2 in India represented 9.1% of this very populous nation. In Pakistan, M172 accounted for 11.9% of the Y-Chromosomes typed. Sengupta's paper broke down the frequencies of Haplogroup J2 into various caste and language groups. J2 was found to be significantly higher among Dravidian castes at 19% than among Indo-European castes at 11%. J2a-M410 in particular may be a strong candidate for a proposed migration of proto-Dravidian peoples from the Iranian Plateau or the Indus Valley since J2a M410 is a very high component of the haplogroup J2 chromosomes found in Pakistan. Over 71% of the M172 found in Pakistan was M410+.

Another interesting characteristic in the distribution of M172 and more specifically, M410, in India was its higher frequencies in Upper Caste Dravidians. M410+ chromosomes were found in 13% of Upper Caste Dravidians. Sengupta goes on to suggest an Indian origin of Dravidian speakers but from a Y chromosome perspective, the paper seems to acknowledge M172 arriving in India from Middle Eastern and Indus Valley Civilizations.

Despite an apparent exogenous frequency spread pattern of J2a toward North and Central India from the west, it is premature to attribute the spread to a simplistic demic expansion of early agriculturists from the Middle may also reflect subsequent Bronze Age Harappans of uncertain provenance.

Subclades of M172 such as M67 and M92 were not found in either Indian or Pakistani samples which also might hint at a partial common origin. And while there may be multiple events and origins for M172 lineages in India, it does seem likely that the Indus Valley and Elamo-Dravidian speaking groups may be the origin of some of the M172 found in India today.


Al Aburto said...

Sengupta et al (2006) did a nice summary table & chart for J2a*-M410. What is needed now is for someone to do a more detailed study of J2a1-S57 and J2a1-L24 :-) ... hopefully in the near future. Al Aburto

Anonymous said...

I believe that all the hapogroup was originated at iran, and then spread mainly to the old aryavrat.
More investigation is needed on this.

He did a very nice work on this.