Revisiting the Schreiter Collection: A Multi-Proxy Study of Genomic Diversity, Paleodiet, and Geographic Mobility in the South-Central Andes

Andean societies have been shaped by complex population movements, interaction networks, and cultural particularities since early periods of occupation. Despite the growing body of biomolecular research on past Andean lifeways, areas such as Northwest Argentina (NWA) remain underexplored. Positioned at a geographic intersection between the Andean Cordillera and the eastern lowlands of the Southern Cone, this region is essential for understanding past population dynamics across the continent. This research applies stable isotope analyses, complete mitochondrial genome sequencing, and radiocarbon dating to study pre-colonial individuals from the Schreiter Collection, an archaeological assemblage from the Quebrada de Villa Vil in NWA, to investigate paleodiet, mobility, and genomic diversity among ancient South-Central Andeans. This study arises from the interests of Argentine archaeologists to recontextualize individuals from the Schreiter Collection as part of ongoing research and community engagement efforts in the High Valleys of NWA, and research outcomes will support local communities in knowledge production and identity-building.

Stable isotope analyses (δ13C, δ15N, and δ18O) suggest heavy maize consumption, camelid protein supplementation, and crop fertilization practices, distinct weaning diets with increased C3 plant consumption, and minimal geographic mobility. Individuals from the Schreiter Collection exhibit mtDNA haplogroups A2+64 (66.67%), D1g5a (16.67%), and C1b (16.67%), which indicates genetic differentiation from Central Andean populations. Shared haplotypes with ancient individuals from Quebrada de Humahuaca and Calchaquí Valley suggest integration into regional exchange networks that facilitated gene flow, and a D1g5a mitogenome closely related to ancient individuals from Central Argentina and the Pampas supports evidence for population interactions between the South-Central Andes and the eastern lowlands. Isotopic uniformity and a regionally-distinct distribution of matrilines suggests a cohesive and well-established community identity in Quebrada de Villa Vil, while affinities with other ancient populations emphasize the differing scales of regional interaction networks.