Chiara Barbieri

CHIARA BARBIERI, Max Planck Institute, Jena, Germany, was awarded a grant in April 2017 to aid research on ‘Using Genomics to Test Models of Language Diffusion: A Case-study on Quechua Diversification.’ Language diversification is shaped by demographic history, as well as by how culture, social structures, and ecology influence human interaction. This project examined a case study from the Andes with Quechua, the most spoken indigenous language family of South America. The diffusion of Quechua was facilitated by the expansion of the Inca empire and by the Spanish colonial policies, but it is not clear if the process was driven by demographic spread or by cultural diffusion alone. The funded project searched for demographic connections by generating genomic data from understudied regions of northern Peru, Ecuador, and Colombia, targeting Quechua-speaking populations and non-Quechua speaking neighbors. The broad genetic structure retrieved separates the Andes from the Amazonia, cutting through similar ethnolinguistic backgrounds. A third, previously unreported ancestry was found in northwestern Amazonia. On top of this ancient structure, shared genomic blocks from a common ancestor correspond to population demographic exchanges. These are found between most Quechua speakers from the Central/Southern Andes and, in minor way, between Quechua speakers of northern regions across ecogeographic domains. These results support demographic connections behind the diffusion of southern Quechua varieties and a mix of demographic and cultural contact for the northern Quechua varieties.