Access Type

Open Access Embargo

Date of Award

January 2021

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Anthropology

First Advisor

Julie J. Lesnik

Abstract

Successful adaptation to the high-elevation Andes would have required both cultural and biological adaptations by early human populations. These past adaptations continue to shape the evolutionary outcomes of both humans and non-human species today. A multispecies perspective was used to examine how humans and non-human creatures, specifically insects, were shaped by past human adaptations. This dissertation asked two primary questions: 1) Given the importance and evolutionary history of potato consumption in the Peruvian Andes, is a genetic adaptation to better digest potato starch detectable in present-day Peruvians? and 2) Using the Andean Potato Weevil (APW) phylogeny as a proxy, what were the patterns of ancient human migration associated with the domesticated potato in the Peruvian Andes? Several selection scan statistics including: LSBL, Tajima’s D, and XP-nSL detected a strong signal of selection for a regional haplotype within the MGAM gene in Peruvian individuals from the 1000 Genomes Project. MGAM encodes for several enzymes associated with the final stage of starch digestion in the small intestine. With the XP-EHH statistical test, this haplotype was estimated to have arisen in Peruvians about 7,950 years ago. This age corroborates to the beginnings of potato domestication, about 8,000 to 10,000 BP, in the southern Peruvian Andes. To further investigate patterns of ancient human migration during this period of early potato domestication, 10 species of the Peruvian APW complex were sequenced and applied toward phylogenetic analyses with Bayesian Inference (BI) and maximum likelihood (RAxML). Due to unique behavioral and biological restrictions, speciation of the APW complex likely occurred when humans unknowingly carried this pest inside their potatoes to new regions of the Andes. Phylogenetic analyses indicate on-going migration and population interaction between communities in the central-southern Peruvian Andes, and a delayed back migration to the south-central Peruvian Andes after northern Andean communities were isolated for some time. Two species of Peruvian APW were also de novo whole-genome sequenced to provide a genomic foundation for future pest management solutions. These results highlight the importance of using a co-evolutionary approach, which can contribute to an anthropological understanding of both past and present human adaptation in the Americas.

Available for download on Saturday, December 09, 2023

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