A new DNA study of unprecedented size has unveiled ancient human movements that shaped the genetic makeup of present-day South Asians in complex ways. Those long-ago treks across vast grasslands and through mountain valleys may even have determined the types of languages still spoken in a region that includes what’s now India and Pakistan.
The investigation addresses two controversial issues. First, who brought farming to South Asia? Genetic comparisons indicate that farming was either invented locally by South Asian hunter-gatherers or launched via borrowing of knowledge from other cultures, rather than brought by Near Eastern farmers from what’s now Turkey. No DNA signs were found of those farmers, who earlier studies suggested had brought farming to Europe. Second, where did local languages originate? New DNA evidence supports the idea that mobile herders from Eurasian steppe grasslands, not Near Eastern farmers, brought Indo-European languages to South Asia.
Ancient DNA had already suggested that Indo-European speaking Eurasian herders called the Yamnaya reached parts of early Bronze Age Europe by around 5,000 years ago (SN: 11/15/17). Yamnaya-related ancestry appeared among South Asians between around 3,900 and 3,500 years ago, an international team reports in the Sept. 6 Science.
“By the early Bronze Age, human movements were stirring the genetic pot throughout Asia,” says archaeologist Michael Frachetti of Washington University in St. Louis. He led the massive project along with Harvard Medical School geneticists David Reich and Vagheesh Narasimhan and archaeologist Ron Pinhasi of the University of Vienna.
What stands out, Frachetti adds, is that Eurasian herders entered South Asia urban centers in relatively small numbers. Thus, a South Asian transition to speaking Indo-European tongues need not have resulted from a large wave of herders rapidly migrating into the region. Scientific scenarios of language change have often been predicated on movements of entire populations that transformed how people spoke elsewhere.
Read more: Science News