Though I cannot find the article in the current issue of the Proceedings of the National Academies of Science to really get at the meat of the article, I feel that this National Geographic News article titled, “India Acquired Language, Not Genes, From West, Study Say” suffices to blog on.
Conducted by Vijendra Kashyap, director of India’s National Institute of Biologicals in Noida the study concludes that the “Indian subcontinent may have acquired agricultural techniques and languages—but it absorbed few genes—from the west.” Adding,
“The finding disputes a long-held theory that a large invasion of central Asians, traveling through a northwest Indian corridor, shaped the language, culture, and gene pool of many modern Indians within the past 10,000 years.That theory is bolstered by the presence of Indo-European languages in India, the archaeological record, and historic sources such as the Rig Veda, an early Indian religious text.”
This was accomplished by sampling the 936 Y chromosomes of men from 32 tribal and 45 caste groups throughout India and the data revealed that the large majority of modern Indians descended from South Asian ancestors who lived on the Indian subcontinent before an influx of agricultural techniques from the north and west arrived some 10,000 years ago.
But how then does this genetic data correlate with the prevalance of Indo-european languages in India, especially northern India… Kashyap and his colleagues say their findings may explain the prevalence of Indo-European languages, such as Hindi and Bengali, in northern India and their relative absence in the south. He also argues that even wholesale language changes can and do occur without genetic mixing of populations. Kashyap says,
“The fact the Indo-European speakers are predominantly found in northern parts of the subcontinent may be because they were in direct contact with the Indo-European migrants, where they could have a stronger influence on the native populations to adopt their language and other cultural entities… It is generally assumed that language is more strongly correlated to genetics, as compared to social status or geography, because humans mostly do not tend to cross language boundaries while choosing marriage partners. Although few of the earlier studies have shown that language is a good predictor of genetic affinity and that Y chromosome is more strongly correlated with linguistic boundaries, it is not always so. Language can be acquired [and] has been in cases of ‘elite dominance,’ where adoption of a language can be forced but strong genetic differences remain [because of] the lack of admixture between the dominant and the weak populations.”
If steppe-dwelling Central Asians did lend language and technology, but not many genes, to northern India, the region may have changed far less over the centuries than previously believed.