THE first humans to arrive in India from Africa about 65,000 years ago left a genetic 鈥渇ootprint鈥� still visible in the DNA of the country鈥檚 tribes.
Anthropologists have hotly debated the country鈥檚 genetic make-up because of its complex history of migrations. So Vadlamudi Raghavendra Rao of the in Kolkata and his team analysed 2768 samples of mitochondrial DNA 鈥� inherited only through our mothers 鈥� from 24 tribes all across the Indian subcontinent (BMC Evolutionary Biology, ).
The team looked for a set of mutations called the M2 haplogroup, which is unique to India and is a subgroup of the M haplogroup of the first migrants to India. They discovered that M2 appeared in India about 50,000 years ago, and makes up nearly 10 per cent of the modern tribes鈥� mitochondrial DNA (see map).
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The M2 鈥渟ignatures of earliest antiquity鈥�, as Rao puts it, cut across major linguistic barriers 鈥� both the Dravidian and Austro-Asiatic language groups share these genetic markers. The traces of the earliest settlers are 鈥渘ot restricted to one particular language family, or one particular population鈥�, says team member Satish Kumar.
Rao agrees: 鈥淏iologically, there are no castes and tribes, there are only communities.鈥�
Genetics 鈥� Keep up with the pace in our continually updated special report.
