Nicobar tribe genetically linked to South and Southeast Asia: Study

While previous studies had stated that the dispersal of the Austroasiatic population (languages commonly spoken in Southeast Asia and the Pacific) in South Asia began some 4,500 – 5,000 years ago and their migration spread many agricultural practices, knowledge of plants and domesticating animals, this is for the first time that such detailed genetic analyses of this tribe were conducted.

The genomic analysis of 1,559 people from this tribe linked the Nicobarese people’s genetic proximity with the Austroasiatic language-speaking Htin Mal communities living along Thailand-Laos’s Nan province.

” The Nicobarese have genetic lineage with the Southeast Asians. This is for the first time we have a detailed genetic proof,” said Gyaneshwar Chaubey, lead author of the study and anthropologist at the Banaras Hindu University.

Along with BHU the study, published on Friday in the European Journal of Human Genetics, was jointly carried out by researchers from CSIR – Centre for Cellular and Molecular Biology, Birbal Sahni Institute of Palaeosciences, Academy of Scientific and Innovative Research, Amrita Viswa Vidyapeetham, University of Calcutta, Tata Institute for Genetics and Society and the University of Bern, Switzerland.

In the numerous evolutionary studies and documentation since the stone-age era, humans are believed to have transitioned from being hunter-gatherers into those living in settlements practising food cultivation, agriculture and animal rearing. But researchers argued that the Nicobarese tribe had a different evolutionary history, especially with respect to their living.

They said that the Nicobarese people and their livelihood practices have links dating back 5,000 years ago. Back then, the Southeast Asian community were extensively involved in farming and agriculture. As food was in grown and available in abundance, these communities thrived and their population exploded. There arrived a point when some from within the community were forced to expand their agri-practices into newer geographical territories, one of them being the Nicobar islands.

“The Nicobarese migrated into Nicobar islands some 4,500 – 5,000 years ago. Interestingly, both men and women migrated to the islands,” Chaubey said.

The study’s co-author and senior scientist specialising in human genetics, Kumarswamy Thangaraj from CCMB, said that this tribal community needs to be protected .

“They need to be allowed to live in their habitat so that the chances of them being exposed to pathogens, which the mainlanders have been exposed to, is limited,” said Thangaraj, who was part of the 2003 team which visited Nicobar islands for sample collection. He recalled treacherous interiors and isolated localities where the Nicobarese lived.

What makes this ancient tribe significant is that they have, so far, lived and survived without admixtures and thereby been able to preserve their genomic origins, language and maintain a remarkable ethnic distinctness over thousands of years. DNA

In DNA, some regions mutate fast and show variations, whereas some other regions upon mutation stabilise and remain unchanged for even thousands of years. The latter kind of genomic markers and the advanced technology helped researchers in unravelling the genomic past in this study.

” As these tribes have stayed isolated for thousands of years, we could obtain and study these stable DNA markers,” said Thangaraj.

At present, there is a 25,000 member community thriving amidst thick forests, living largely by rearing pigs, goat and hen along with being dependent on forest-produce like coconut palm.