In a new insight into the origin and history of surviving indigenous tribes of the Andaman Islands, an analysis of their DNA, showed that although they look closely related to Asians, they have actually descended from those who migrated eastward out of Africa.
“This is the first detailed molecular genetic evidence on the affinities of the Andaman Islanders, the small-statured hunter-gatherers, arguably the most enigmatic people on the planet. The mystery of their origin is now unravelled,” said Lalji Singh, Director of the Cellular and Molecular Biology (CCMB), based here, which has undertaken the analysis, after signing an MoU with the Anthropological Survey of India.
The results of the study by Dr. Singh, Thangaraj Kumaraswamy and other scientists, have been published in the leading international journal “Current Biology” (January 21, 2003), with the title “Genetic Affinities of the Andaman Islanders, a Vanishing Human Population.” The other institutions involved in the study were the Stanford University, California, University of Otago, Dunedin, New Zealand and the University of Oslo, Norway.
Dr. Singh and his team analysed DNA from the present-day Andamanese of the Onge, Jarawa and Great Andamanese tribes and inhabitants of the neighbouring Nicobar Islands. Blood samples preserved at the Regional Medical Research Centre at Port Blair were used. Another feature of the study was the analysis of the DNA from the Andamanese hair locks, collected by a British ethnographer, a century ago.
The genetic data, which included maternally-inherited mitochondrial DNA and paternal Y chromosome-markers, conformed to the “out of Africa” theory and suggested that the Andaman Islanders descended from early humans who migrated eastward out of Africa during the last ice age, 60,000 to 100,000 years ago. They could be descendants of the early Palaeolithic colonisers of Southeast Asia.
Having close relations to Asians than to Africans, they probably split from other Asian populations tens of thousands of years ago. The Nicobarese, in contrast, have genetic affinities to groups widely distributed throughout Asia today and presumably descended from Neolithic agriculturalists.
The living Andamanese showed low genetic variability consistent with their small population size and reproductive isolation.
Cut off from the modern world, for centuries these tribes gave a fierce fight to anyone who tried to intrude into their land and privacy. Many of them have perished and a few surviving ones are on the verge of extinction, falling prey to “pacification” and disease. The four surviving tribes — Jarawa, the Great Andamanese, the Onge and the Sentinelese, can be counted — 200, 36, 98 and 250 respectively.
Sometimes known as `Negritos,’ they share physical features as short stature, dark skin, peppercorn hair, scant body hair and steatopygia with African pygmies and other Asian Negrito people. “Their origins were really a mystery. No one knows where they came from? How long they have been there? Could these islanders hold the key to the mystery of our own origins? Their world could serve as a window to look into the past showing us how we were hundred thousand years ago when the first modern humans left Africa. The DNA analysis now provides some answers,” Dr. Singh said.
He said the DNA analysis on Andamanese was part of a bigger study on tribes all over India. In fact some tribes having genetic make-up similar to Jarawa and the Onges, have been found in Gujarat and Kerala, possibly indicating the route of migration. The ancestors of these tribes in the two States were much older than those in Andamans.
The next part of the study would focus on the disease susceptibility genes and the impact of the environment on such susceptibility.
“The study is not merely to trace the origins and history but to understand the disease dynamics and find solutions to the suffering people.”