Ancient human mitochondrial (mtDNA). Analysis form the Pampean region of Argentina. New results and perspectives

PABLO MESSINEO; MARIELA GONZÁLEZ; GUSTAVO POLITIS; NAHUEL SCHEIFFLER; CLARA SCABUZZO; LARS FEHREN-SCHMITZ

Simposio; 9° Simposio del Hombre Temprano; 2018

Archaeological excavations of three open-air sites in the Pampeanregion of Argentina revealed a large numbers of human burials for theEarly and Middle Holocene. The analysis of ancient mitochondrial DNAfrom these human remains generated new results about the peopling of theAmericas and provided new insight about population dynamic in thisregion. At the Arroyo Seco 2 site 50 individuals (and counting), datedbetween 7819 ± 61 and 4487 ± 45 14C yrs BP were recovered (n = 26 dates).We obtained 13 full mitochondrial genomes from those. In Laguna Chicathree humans skeletons were dated between 6080 ± 15 and 5930 ± 15 14Cyrs BP (n = 2 dates). A forth skeleton produces a more recent age (1750 14Cyrs BP). Among them, we generated three full mitochondrial genomes.Finally, at the Laguna de los Pampas site, 6 skeletons were dated between8971 ± 77 and 5688 ± 36 14C yrs BP (n = 6 dates). We were able to obtainthe full mitogenome of the older dating individual (Burial 1, Individual 1).In this presentation, we compared the mitochondrial genomes from thethree sites to existing ancient and modern mitochondrial genomes fromSouth America to reconstruct the phylogenies of the Native Americanfounding lineages and to date the divergence of Southern Cone specifichaplotypes. We find long standing genetic continuity in the Pampeanregion, with some of the Early and Middle Holocene mitochondriallineages being basal to lineages found in modern and historic populations ofthe Pampas and Patagonia. We further determine divergence ages of ~11kyears for the Southern Cone specific lineages D1j and D1g, confirming thatthose lineages evolved shortly after the first people arrived in the Pampasand further south.