Biocultural Evolution of the Oral Complex in Coastal Atacama and the Interplay of Selection, Plasticity, and Population Histories

Summary

Indigenous groups have inhabited and exploited the coastal valleys of the Atacama Desert since Paleoindian times. Contact with the altiplano began early on but marine-based diets were eventually supplemented by agricultural adaptations as influence turned to population movement over time. We propose that the oral complex was likely subject to some degree of selection early in the sequence in response to dietary demands, but would have been relaxed as diet diversified and softened. This trend would subsequently have been disrupted by the influx of different populations from surrounding areas. We test these hypotheses by examining crown dimensions, evidence for decay and defects, and wear rates in a sample of 591 individuals (15,398 teeth) from archaeological sites in the Azapa Valley of northern Chile that span most of the precontact cultural sequence in the region. Results indicate that social changes over time, particularly diet composition and food consistency, caused steady increases in decay and defects. In contrast tooth wear was variable across time likely reflecting the continued consumption of local marine resources. Finally, fluctuating crown dimensions, enamel damage, and evidence for directional asymmetry may reflect the complex interplay between relaxing selection and gene flow.

This Resource is Part of the Following Collections

• Evolutionary Adaptations and Population History of the Atacama Desert   •
• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)

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Record Identifiers

Abstract Id(s): 14571