The genetic build of Indians was set nearly 2000-4000 years ago with the inter-mixing of settlers from abroad and indigenous people, a study reveals.
According to the findings, published today, the emergence of caste system in India enhanced intra-caste marriages or endogamy which "froze" further inter-mixing of population resulting in present day genetic structure of various groups in the country.
Kumarasamy Thangaraj of the Cellular and Molecular Biology in Hyderabad who was part of the research told PTI that caste system enhanced endogamy -- marriages taking place within a community -- which shaped genetic profiles found in present-day populations.
He said incidence of genetic diseases, which are population specific, tend to have increased in last few thousand years with the rise in endogamy adopted by various castes in the country.
The research, published in American Journal of Human Genetics, is an attempt to develop information about the changes that led to present-day genetic build of Indians.
"Prior to the population mixture and as recently as a few thousand years ago, the population structure of India was profoundly different from what it is today," co-senior author Dr David Reich of Harvard Medical School in Boston said in a statement.
The findings show that mixing of these populations occurred about 1,900-4,200 years ago.
Reich's team and investigators at Centre for Cellular and Molecular Biology in Hyderabad conducted genetic analysis of 73 groups from the sub-continent showing that present population is the mixture of two ancestral groups--Ancestral North Indians (ANI) related to Central Asians, Middle Easterners, Caucasians, and Europeans and Ancestral South Indians (ASI) which were not closely related to groups outside the subcontinent.
