caste system existed from 'Founder' race: CCMB-Harvard-MIT study
Hyderabad | Thursday, Sep 24 2009 IST
The caste system in India was in existence since the hoary days and all Indian groups including Aryans and Dravidians, decended from a ''mixture of two ancestral population'', a new study by Indian and Americans genetists has revealed. The new research reveals 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 one exception to the finding that all Indian groups are mixed are the indigenous people of the Andaman Islands, an archipelago in the Indian Ocean with a census of only a few hundred today. The Andamanese appear to be related exclusively to the Ancestral South Indian lineage and therefore lack Ancestral North Indian ancestry.
The study, an international effort is the first genome-scale analysis of diverse Indian groups, which has medical implications for people of Indian descent, was led by scientists at the Centre for Cellular and Molecular Biology (CCMB) in Hyderabad together with US researchers at Harvard Medical School, the Harvard School of Public Health and the Broad Institute of Harvard and MIT.
In the study published in the September 24 issue of Nature, an international team describes how they harnessed modern genomic technology to explore the ancient history of India, the worlds second most populous nation. The researchers--work also has surprising and important medical implications--discovered that many groups in modern India descend from a small number of founding individuals, and have since been genetically isolated from other groups. In scientific parlance this is called a ''founder event.'' 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. The widespread history of founder events helps explain why the incidence of genetic diseases among Indians is different from the rest of the world, geneticists say.
Founder events in other groups, such as Finns and Ashkenazi Jews, are well known to increase the incidence of recessive genetic diseases, and the new study predicts that the same will be true for many groups in India. It is important to carry out a systematic survey of Indian groups to identify which ones descend from the strongest founder events. ''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,'' the genetists group said.
-- (UNI) -- 24MS66.xml
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