India is one, genetically

Syed Akbar

Hyderabad:  India has 4,693 different, documented population groups that include 2205 major communities and 1900 territorial units spread across the country, but Indians are one, genetically speaking.

Joint studies by the Centre for DNA Finger-printing and Diagnostics, Hyderabad, and the National DNA Analysis Centre of Central Forensic Science Lab, Kolkata, revealed no evidence of general clustering of population groups based on ethnic, linguistic, geographic or socio-cultural affiliations.

Indian populations endowed with unparalleled genetic complexity have received a great deal of attention from scientists world over. The scientists of CDFD and CFSL studied the underlying genetic structure of 3522 individuals belonging to 54 endogamous Indian populations representing all major ethnic, linguistic and geographic groups.

"The distribution of the most frequent allele was uniform across populations, revealing an underlying genetic similarity. Patterns of allele distribution suggestive of ethnic or geographic propinquity were discernible only in a few of the populations and was not applicable to the entire dataset," they said.

Analysis of molecular variance failed to support the geographic, ethnic, linguistic or socio-cultural grouping of Indian populations suggesting little variation between the different groups.

However, genetic sub structuring was detected among populations originating from north-eastern and southern India reflective of their migrational histories and genetic isolation respectively.

Populations such as Thakur and Khatri from Uttar Pradesh and Baniya from Bihar showed similarity with southern populations such as Naikpod Gond and Chenchu from Andhra Pradesh and with a few individuals from Maharashtra and Lepcha of Sikkim. Of the southern populations, those from Karnataka and Andhra Pradesh were differentiated into two groups with populations from Tamil Nadu exhibiting split membership to both groups.

In the East, Bihar Brahmin, Bhumihar, Kayasth, Rajput, Yadav, Bihar Kurmi, Orissa Brahmin, Khandayat, Karan, Juang and Paroja shared similar membership to multiple clusters revealing a common genetic structure.

In the south, Lingayat, Gowda, Brahmin and Muslim of Karnataka along with Vanniyar, Gounder and Pallar of Tamil Nadu separated from rest of the populations.

Rest of the populations from Tamil Nadu; Chakkiliyar, Paraiyar, Tanjore Kallar and from Andhra Pradesh; Brahmin, Raju, Komati, Kamma Chaudhury, Kapu Naidu, Reddy and Lambadi displayed mixed membership to multiple clusters.

Populations from western and central India showed absence of any distinct grouping with individuals having symmetrical membership across inferred clusters.

"The results reveal genetic similarity across populations with a few presenting distinct identities that did not follow traditional groupings of geography, language or ethnicity. Populations from southern India and north-eastern India largely exhibited structuring while most Indian populations shared similar membership in multiple clusters," the study said.