Sunday, December 18, 2005

On the origins of Indians

The Indo-European languages of India were supposedly brought in by invaders from Central Asia, along with the horse; and these invaders displaced both the elite and the previous languages - such is what goes under the name of Aryan Invasion Theory (AIT) or the more politically correct Aryan Migration Theory (AMT).

There are many good reasons not to accept this theory, even though there is no really coherent replacement theory. Nevertheless, non-acceptance of this theory gets one branded as a "Hindu fundamentalist", a "nationalist bigot" and so on. (Even though at least two of the proponents of AIT/AMT do count as heroes to the Hindu right - Tilak and Savarkar).

Anyway, AMT/AIT theory is in trouble (via Rajita Rajvasisht in the IndianCivilization yahoo egroup, but she omitted the publication name!)

Polarity and Temporality of High-Resolution Y-Chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists

Sanghamitra Sengupta,1 Lev A. Zhivotovsky,2 Roy King,3 S. Q. Mehdi,4 Christopher A. Edmonds,3 Cheryl-Emiliane T. Chow,3 Alice A. Lin,3 Mitashree Mitra,5 Samir K. Sil,6 A. Ramesh,7 M. V. Usha Rani,8 Chitra M. Thakur,9 L. Luca Cavalli-Sforza,3 Partha P. Majumder,1 and Peter A. Underhill3

1 Human Genetics Unit, Indian Statistical Institute, Kolkata, India;
2 N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow;
3 Department of Genetics, Stanford University, Stanford;
4 Biomedical and Genetic Engineering Division, Dr. A. Q. Khan Research Laboratories, Islamabad;
5 School of Studies in Anthropology, Pandit Ravishankar Shukla University, Raipur, India;
6 University of Tripura, Tripura, India;
7 Department of Genetics, University of Madras, Chennai, India;
8 Department of Environmental Sciences, Bharathiar University, Coimbatore, India; and
9 B. J. Wadia Hospital for Children, Mumbai, India

Received July 26, 2005; accepted for publication November 3, 2005;
electronically published December 16, 2005.

Although considerable cultural impact on social hierarchy and language in South Asia is attributable to the arrival of nomadic Central Asian pastoralists, genetic data (mitochondrial and Y chromosomal) have yielded dramatically conflicting inferences on the genetic origins of tribes and castes of South Asia. We sought to resolve this conflict, using high-resolution data on 69 informative Y-chromosome binary markers and 10 microsatellite markers from a large set of geographically, socially, and linguistically representative ethnic groups of South Asia. We found that the influence of Central Asia on the pre-existing gene pool was minor. The ages of accumulated microsatellite variation in the majority of Indian haplogroups exceed 10,000–15,000 years, which attests to the antiquity of regional differentiation. Therefore, our data do not support models that invoke a pronounced recent genetic input from Central Asia to explain the observed genetic variation in South Asia. R1a1 and R2 haplogroups indicate demographic complexity that is inconsistent with a recent single history. Associated microsatellite analyses of the high-frequency R1a1 haplogroup chromosomes indicate independent recent histories of the Indus Valley and the peninsular Indian region. Our data are also more consistent with a peninsular origin of Dravidian speakers than a source with proximity to the Indus and with significant genetic input resulting from demic diffusion associated with agriculture. Our results underscore the importance of marker ascertainment for distinguishing phylogenetic terminal branches from basal nodes when attributing ancestral composition and temporality to either indigenous or exogenous sources. Our reappraisal indicates that pre-Holocene and Holocene-era—not Indo-European—expansions have shaped the distinctive South Asian Y-chromosome landscape.


The URL is:

The American Journal of Human Genetics, Posted: Dec. 16, 2005.


CapitalistImperialistPig said...

I don't quite understand this abstract. There seems to be little information that explains either the reasoning or the main lines of evidence.

I don't have a dog in the fight over Central Asian immigration, but it would seem distinctly odd for a people to adopt a foreign language without some sort of powerful military or cultural motivation.

Arun said...

I'll reply in blog posting.