Wednesday, 13 August 2008
Languages have no genetic basis, says CCMB
August 13, 2008
By Syed Akbar
Hyderabad, Aug 12: Languages have no genetic basis, says a research study by the city-based Centre for Cellular and Molecular Biology.
In an international study carried out by CCMB in association with the University of Tartu, Estonia, Universia di Pavia, Italy and the University of Cambridge, the researchers there was a "significant correlation between genetic variation and geography, rather than between genes and languages". This is other words means languages have no genetic basis.
"Human genetic diversity observed in Indian subcontinent is second only to that of Africa. This implies an early settlement and demographic growth soon after the first 'Out-of-Africa' dispersal of anatomically modern humans in Late Pleistocene. In contrast to this perspective, linguistic diversity in India has been thought to derive from more recent population movements and episodes of contact. With the exception of Dravidian, which origin and relatedness to other language phyla is obscure, all the language families in India can be linked to language families spoken in different regions of Eurasia," said Dr K Thangaraj, senior scientist with the CCMB.
Mitochondrial DNA and Y chromosome evidence has supported largely local evolution of the genetic lineage of the majority of Dravidian and Indo-European speaking populations, but there is no consensus yet on the question of whether the Munda (Austro-Asiatic) speaking populations originated in India or derive from a relatively recent migration from further East.
The research team analysed 35 novel complete mitochondrial DNA sequences from India which refine the structure of Indian-specific varieties of haplogroup "R". Detailed analysis of haplogroup R7, coupled with a survey of around 12,000 mitochondrial DNAs from caste and tribal groups over the entire Indian subcontinent, reveals that
one of its more recently derived branches (R7a1), is particularly frequent among Munda-speaking tribal groups.
More than one sixth of humanity currently lives on the Indian subcontinent. This population is spread across up to 40,000 endogamous and semi-endogamous culturally, linguistically, and socially differentiated groups. The majority of these groups or
populations are castes, but they also include nearly 500 'scheduled tribes' and 500 'scheduled castes'.
"Thus, the Indian subcontinent is an ideal region for studying the relationships between culture, geography and genes, and for developing interdisciplinary models concerning the demographic history of Homo sapiens or anatomically modern humans," he said.
It has been argued, that following the initial colonisation of Indian subcontinent, maternal gene flow from the west has been rather limited and largely restricted to the western states of contemporary India and Pakistan.
Consequently, the haplogroup richness of the Indian subcontinent appears to have formed in situ, and date back to some point in the later Pleistocene. Furthermore, this high level of genetic diversity may also be linked to the possibility that the South Asian population in the Pleistocene was demographically large in global terms.
Similarly, the Indian tribes speaking different Munda languages show generally the same mtDNA haplogroup composition as the Indo European and Dravidic groups of India. In contrast, the Y chromosomes of Indian and Southeast Asian AA speaking populations
share a common marker.
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