Ancient mitogenomes from the Southern Pampas of Argentina reflect local differentiation and limited extra‐regional linkages after rapid initial colonization

• Published in: American journal of biological anthropology Vol. 181; no. 2; pp. 216 - 230
• Main Authors: Motti, Josefina M. B., Pauro, Maia, Scabuzzo, Clara, García, Angelina, Aldazábal, Verónica, Vecchi, Rodrigo, Bayón, Cristina, Pastor, Nicolás, Demarchi, Darío A., Bravi, Claudio M., Reich, David, Cabana, Graciela S., Nores, Rodrigo
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-06-2023; Wiley Subscription Services, Inc
• Subjects: ancient DNA; Archaeological evidence; Argentina; Bayes Theorem; Bayesian analysis; Colonization; Deoxyribonucleic acid; Differentiation; DNA; Genetic drift; Genome, Mitochondrial - genetics; Genomics; Haplotypes; Human populations; Humans; Indigenous peoples; mitochondrial DNA; native Americans; Pampas; Pampas region; Phylogeny; Regional variations; Regions; South America; Southern Cone; South America; Argentina; ancient DNA; Pampas region; mitochondrial DNA; native Americans; Southern Cone
• ISSN: 2692-7691; 2692-7691
• DOI: 10.1002/ajpa.24727

Objective
This study aims to contribute to the recovery of Indigenous evolutionary history in the Southern Pampas region of Argentina through an analysis of ancient complete mitochondrial genomes.
Materials and Methods
We generated DNA data for nine complete mitogenomes from the Southern Pampas, dated to between 2531 and 723 cal BP. In combination with previously published ancient mitogenomes from the region and from throughout South America, we documented instances of extra‐regional lineage‐sharing, and estimated coalescent ages for local lineages using a Bayesian method with tip calibrations in a phylogenetic analysis.
Results
We identified a novel mitochondrial haplogroup, B2b16, and two recently defined haplogroups, A2ay and B2ak1, as well as three local haplotypes within founder haplogroups C1b and C1d. We detected lineage‐sharing with ancient and contemporary individuals from Central Argentina, but not with ancient or contemporary samples from North Patagonian or Littoral regions of Argentina, despite archeological evidence of cultural interactions with the latter regions. The estimated coalescent age of these shared lineages is ~10,000 years BP.
Discussion
The history of the human populations in the Southern Pampas is temporally deep, exhibiting long‐term continuity of mitogenome lineages. Additionally, the identification of highly localized mtDNA clades accords with a model of relatively rapid initial colonization of South America by Indigenous communities, followed by more local patterns of limited gene flow and genetic drift in various South American regions, including the Pampas.