An ethnolinguistic and genetic perspective on the origins of the Dravidian-speaking Brahui in Pakistan

Pakistan is a part of South Asia that modern humans encountered soon after they left Africa ∼50-70,000 years ago. Approximately 9,000 years ago they began establishing cities that eventually expanded to represent the Harappan culture, rivalling the early city states of Mesopotamia. The modern state constitutes the north western land mass of the Indian sub-continent and is now the abode of almost 200 million humans representing many ethnicities and linguistic groups. Studies utilising autosomal, Y chromosomal and mitochondrial DNA markers in selected Pakistani populations revealed a mixture of Western Eurasian-, South- and East Asian-specific lineages, some of which were unequivocally associated with past migrations. Overall in Pakistan, genetic relationships are generally predicted more accurately by geographic proximity than linguistic origin. The Dravidian-speaking Brahui population are a prime example of this. They currently reside in south-western Pakistan, surrounded by Indo-Europeans speakers with whom they share a common genetic origin. In contrast, the Hazara share the highest affinity with East Asians, despite their Indo-European linguistic affiliation. In this report we reexamine the genetic origins of the Brahuis, and compare them with diverse populations from India, including several Dravidian-speaking groups, and present a genetic perspective on ethnolinguistic groups in present-day Pakistan. Given the high affinity of Brahui to the other Indo-European Pakistani populations and the absence of population admixture with any of the examined Indian Dravidian groups, we conclude that Brahui are an example of cultural (linguistic) retention following a major population replacement.