A molecular analysis of three major tribal populations of Chakma, Marma and Tripura living in the Chittagong Hill Tract of Bangladesh shows they have mainland Indian ancestry.

Researchers at the Centre for Cellular and Molecular Biology here have found that these tribes from Bangladesh showed strikingly high homogeneity among themselves and strong affinities to Tibeto-Burman groups of the North-East.

The team lead by Kumarasamu Thangaraj of CSIR-Centre for Cellular and Molecular Biology, in collaboration with Nurun Nahar Gazi Sultana and her team from Dhaka, studied the origin and affinity of Bangladeshi tribal populations for the first time using all genetic systems that are used for population-based studies.

The results, published recently, offer leads to probable location and ways of human movements from India and Myanmar into Bangladesh.

In a statement, Thangaraj said, “We carried out a detailed genetic analysis of three tribal populations from Bangladesh, who speak a branch of Tibeto-Burman language and compared them with our large data-set from India and South-East Asia, and observed that the Bangladesh Tibeto-Burman populations carry substantially higher mainland Indian ancestry component than North-East India or South-East Asia Tibeto-Burman speaking people.”

The genetic studies so far on South and South-East Asia populations suggest that the expansion of Tibeto-Burman population happened very recently in India from South-East Asia.

According to the study abstract, human settlements and migrations alongside the Bay of Bengal have played a vital role in shaping the genetic landscape of Bangladesh, Eastern India and South-East Asia.

The aim of the study was to trace footprints of initial colonisation and expansion of populations among aboriginal tribal populations. Issues relating to genetic variation were examined and relationships studied leading to these findings.

>rishikumar.vundi@thehindu.co.in

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