Hyderabad: The maternal lineage of north Indians traces to East Asia, says a research study by city-based Centre for Cellular and Molecular Biology, implying that women from the region had settled down in India in the past.
The tiny Himalayan state of Nepal served as a link between East Asia and India when early human beings moved from one region to another. The CCMB scientists based their observations after their study on Tharu people living in the Terai plains between India and Nepal pointed to past human movements from East Asia to India.
"We have analysed 7,137 samples from 125 different caste, tribal and religious groups of India and 99 samples from three populations of Nepal. Analysis of data suggests minor maternal contribution from Southeast Asia to Northern India. Nepal might have served as a bridge for the flow of eastern lineage to India. Moreover the gene flow between India and Nepal has been reciprocal," Dr K Thangaraj of CCMB told this correspondent.
India, being culturally and geographically a highly heterogeneous country, the caste and tribal groups here are considered socially and culturally the most stratified of all known societies in human history. Indian populations are structured further by their linguistic and religious affiliations. More than 60 per cent of the present day Indian maternal lineage is affiliated with mitochondrial DNA haplogroup M, he said.
"Of the 7,137 individuals studied 139 individuals had the haplotype (9-bp deletion) whereas 42 individuals had the insertion. The highest frequency of deletion was observed in Yanadis from Andhra Pradesh. Nine populations showed the presence of the 9-bp insertion and the highest frequency was also observed in a Dravidian-speaking population, from the State," he said.
The CCMB team for the first time identified the rare West Eurasia-specific haplogroup H14 in Indian population. The complete sequencing of the Indian branch suggests a deep split between the Indian and European lineage.
The migration of Southeast Asian maternal lineage to North India has occurred not only through the corridor of Nepal but also has involved gene flow along the southern slopes of the Himalayas within the Indian sub-continent.