Genetic Change in South Patagonia over Seven Millennia

RODRIGO NORES; NATHAN NAKATSUKA; PIERRE LUISI; JOSEFINA MOTTI; DAVID REICH

Congreso; 86th Annual Meeting Online; 2021

Society for American Archaeology

South Patagonia, the austral extreme of South America, has been inhabited for at least 12,600 years. Following European contact, five ethnic groups of hunter-gatherers (Yámana, Kawéskar, Selk?nam, Haush, and Aónikenk) were documented. They based their subsistence in two broad strategies optimized for maritime or terrestrial resources. After a century of fieldwork, archaeologists have revealed a complex pattern of differentiation between groups. Many questions regarding peopling, admixture, and technological changes remain to be answered.In order to provide some hints into those questions, we generated genome-wide data from 20 ancient individuals and compared it to previously reported data. We observed a shared genetic ancestry between maritime and terrestrial Middle Holocene individuals (~6600-5800 BP) that persists in some Late Holocene groups. We also identified two migration events that reached South Patagonia: a first wave by at least ~4700 BP that differentiated Late Holocene maritime groups from terrestrial ones; and gene flow with Central Chile around 2000 BP with major impact in terrestrial groups. Finally, Late Holocene groups fall on a genetic cline precisely correlated to geographic ordering following the coastal line, as a result of the uneven impact of these two migration processes.