India, Feb. 11 -- When a Delhi resident chats in Hindi, they're participating in a linguistic legacy that stretches back about 6,500 years to the grasslands of present-day Russia. This connection is now backed by convincing genetic evidence, thanks to two landmark studies published in Nature this month that trace the origins of languages spoken by nearly half the world's population.

By analysing DNA from 435 ancient individuals, a team led by Harvard geneticist David Reich has solved one of humanity's enduring mysteries. They identified a specific group of people, dubbed the Caucasus Lower Volga (CLV) people, who lived in what is now Russia around 4500 BCE. These people inhabited the region between the Volga River and the northern Caucas...