India's caste system stretches back thousands of years and was not largely a creation of colonial rule, as some historians claim, a genetic study has shown. Researchers analysed the DNA of 132 individuals with wide-ranging backgrounds from 25 diverse groups around India. They found evidence of strong inbreeding leading to genetic groups that had been isolated from each other for thousands of years. Most people had a mixture of genes from two ancient populations representing traditionally upper-caste individuals and everyone else. The first was genetically close to people from the Middle East, Central Asia and Europe, while the second had an 'Ancestral South Indian' lineage confined to the subcontinent. The research challenges the notion that India's notorious rigid caste system, with its priestly Brahmans and low-status 'untouchables', was largely manufactured by the British. The new findings published in the journal Nature indicate that, genetically at least, Indians had been divided long before the British arrived.
560K SNP study reveals dual rigin of Indian populations (Reich et al. 2009)