Genetic diversity in maternal amerindian lineages in Argentinian Patagonia

CRESPO CM; POSTILLONE MB; RUSSO MG; BRAVI CM; AVENA S; FAVIER DUBOIS C; HAJDUK A; ARRIGONI G; LANATA JL; DEJEAN CB

Burgos

Congreso; XVII Congress IUPPS; 2014

Unione Internationale des Sciences Prehistoriques et Protohistoriques

Introduction: Recently new approaches about American regional peopling are being produced from several disciplines and contribute to explain different social and biological aspects from ancient populations. Patagonia, the southern region of South America, presents evidence of early archaeological sites, with an accepted chronology of 14,500 cal BP in Chile and 13,900 ? 12,800 cal BP for Argentinian locations. The study of mitochondrial DNA can be used to determine the genetic structure and the evolutionary history of human groups. Different clades have been described so far in South America. They exhibit different mutations and sometimes a geographic specific dispersion. For example: B2 haplogroup is more frequently found in the Andean region, A2 in extant samples of Argentinian Mesopotamia, and C1, D1, D4h3a and some of their variants in ancient Patagonian groups. The aim of this study is to provide new data about the maternal lineages that inhabited Patagonia during the Late Holocene and determine their regional distribution. Materials and Methods: A total of 58 human samples were analyzed, their chronology go from 4800 ybp to contact period, they  belong to museum collections or archaeological sites from different locations in Patagonia. DNA was extracted after demineralization, proteinase K digestion, organic solvent extraction and concentration with silica columns and/or with QIAamp DNA Investigator kit (Qiagen). Haplogroups were typified by PCR-RFLP and sequencing of the hipervariable region I (HVR I). Analyses were performed to calculate genetic diversity, their association with the geographic distribution (Mantel Test) and the differentiation among Patagonia populations (AMOVA). Results:                                                                                               So far DNA of 33/58 samples (57.0%) could be assigned by RFLP, 19 (57.6%) samples belong to D haplogroup, 12 (36.4%) to C and 2 (6.0%) to A. HVR-I sequences were obtained in 20/33 individuals. The following lineages were identified: A2, C1, D1, D1g, D1j and D4h3a. Statistical analysis revealed that no genetic differentiation would exist among the studied groups. Conclusions: As previously described, most of the individuals analyzed were characterized C1 and D1. We also detected D1j, D1g and D4h3a on the Atlantic coast, traditionally accepted as founder lineages coming south by a Pacific coastal route, and present in extant natives. This raises the question about whether the initial peopling occurred from the Pacific coast with a subsequent expansion or it came from the North through an Atlantic route, or both. Finally, we could postulate a reduced genetic diversity and no population structure, perhaps the result of founder effect and/or genetic flow among the Patagonian natives.