vIndianz.com (Sept. 24, 2009) — An international team revealed that nearly all Indians carry genomic contributions from two distinct ancestral populations. Following this ancient mixture, many groups experienced periods of genetic isolation from each other for thousands of years.
The study, which has medical implications for people of Indian descent, was led by scientists at the Centre for Cellular and Molecular Biology (CCMB) in Hyderabad, India together with US researchers at Harvard Medical School, the Harvard School of Public Health and the Broad Institute of Harvard and MIT.
Although the genome sequences of any two unrelated people differ by just 0.1%, that tiny slice of genetic material is a rich source of information. It provides clues that can help reconstruct the historical origins of modern populations and it also points to genetic variations that heighten the risk of certain diseases.
The research team analyzed more than 500,000 genetic markers across the genomes of 132 individuals from 25 diverse groups, representing 13 states, all six language families, traditionally “upper” and “lower” castes, and tribal groups India.
These genomic analyses revealed two ancestral populations. “Different Indian groups have inherited forty to eighty percent of their ancestry from a population that we call the Ancestral North Indians who are related to western Eurasians, and the rest from the Ancestral South Indians, who are not related to any group outside India,” said co-author David Reich.
The finding that nearly all Indian groups descend from mixtures of two ancestral populations applies to traditional “tribes” as well as “castes.” Kumarasamy Thangaraj, a senior research scientist said, “It is impossible to distinguish castes from tribes using the data.
He added that the widespread history of founder events helps explain why the incidence of genetic diseases among Indians is different from the rest of the world.”
The genetics proves that they are not systematically different. This supports the view that castes grew directly out of tribal-like organizations during the formation of Indian society.”
“The finding that a large proportion of modern Indians descend from founder events means that India is genetically not a single large population, but instead is best described as many smaller isolated populations,” said Lalji Singh, senior author of the Nature paper, who is a Bhatnagar Fellow and the former director of CCMB.
“Further studies of these groups should lead to the rapid discovery of genes that cause devastating diseases, and will help in the clinical care of individuals and their families who are at risk.”
Further Reading- All Indians to be back home from Libya by Friday – Economic Times
- India backs democracy in Egypt, says Indians are safe – Hindustan Times
- 25000 Indians safe in Japan – Hindustan Times
- Chronic disease is biggest killer – BBC News
- Air India responds to allegations of overcharging Indians in Cairo – NDTV.com
- Parents Say Yes to Genetic Testing – CBS42
- Money can buy better health, study finds — if you’re a hospital patient – Los Angeles Times
- Same gene linked to Alzheimer’s and heart attacks – Times of India
- Will do everything to evacuate Indians from Japan: Govt – The Hindu
- Unheard-of hoop glory within Harvard’s grasp – Boston Globe
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