Ancient mitochondrial genomes from the Argentinian Pampas inform the early peopling of the Southern Cone of South America

The Southern Cone of South America (SCSA) is a key region for investigations about the peopling of the Americas. However, little is known about the eastern sector, the Argentinian Pampas. We analyzed 18 mitochondrial genomes-7 of which are novel-from human skeletal remains from 3 Early to Late Holocene archaeological sites. The Pampas present a distinctive genetic makeup compared to other Middle to Late Holocene pre- Columbian SCSA populations. We also report the earliest individuals carrying SCSA-specific mitochondrial haplogroups D1j and D1g fromEarly and Middle Holocene, respectively. Using these deep calibration time points in Bayesian phylogenetic reconstructions, we suggest that the first settlers of the Pampas were part of a single and rapid dispersal similar to 15,600 years ago. Finally, we propose that present-day genetic differences between the Pampas and the rest of the SCSA are due to founder effects, genetic drift, and a partial population replacement similar to 9,000 years ago.

Automated summary

Study of mitochondrial genomes from human skeletal remains in the Argentinian Pampas revealed distinct genetic makeup compared to other South Cone of South America (SCSA) populations, with earliest settlers estimated to have arrived in a single and rapid dispersal around 15,600 years ago. Present-day genetic differences between the Pampas and the rest of SCSA are attributed to founder effects, genetic drift, and a partial population replacement around 9,000 years ago.