The Rakhigarhi samples belonged to individuals who lived approximately 4,600 years ago, during the peak of the Indus Valley Civilisation. The absence of steppe DNA markers in the samples indicates that, at that point in time, there had been no intermingling between the steppe pastoralists and the population of the Indus Valley Civilisation.

Rai had earlier told Open magazine that the male “Y chromosome R1a genetic marker is missing in the Rakhigarhi sample.” The R1a is seen as a marker of Indo-European speakers, but its absence in a single sample is not significant—it is the wider analysis of the entire genome that is important in the context of this sample.

The work by Rai and his team will provide direct evidence for the model proposed by the March 2018 paper from the Reich Lab, which has bearing on a number of questions of great interest pertaining to the Indian past. The preprint states, “Our results also shed light on the question of the origins of the subset of Indo-European languages spoken in India and Europe. It is striking that the great majority of Indo-European speakers today living in both Europe and South Asia harbor large fractions of ancestry related to … Steppe pastoralists … suggesting that ‘Late Proto-Indo-European’—the language ancestral to all modern Indo- European languages—was the language” of the steppe pastoralist population.

In other words, the preprint observes that the migration from the steppes to South Asia was the source of the Indo-European languages in the subcontinent. Commenting on this, Rai said, “any model of migration of Indo-Europeans from South Asia simply cannot fit the data that is now available.”