Doctoral Dissertation Research: Using Ancient Crop DNA to Investigate Socio-Political Change

Iowa State University, Ames IA

Investigators

Abstract

This doctoral dissertation project addresses the question of the co-evolution of humans and maize and considers how human behavior influences maize evolution in a specific geographic context. The research integrates multiple lines of data to address these goals, including ancient maize genetics, radiocarbon dating, and the relevant archaeological record. The project documents early maize traits that were subject to human selection, shedding light on relevant political and ethnic influences and how they affected the process over time. The project is underpinned by inclusivity, with a focus on broadening the participation of underrepresented groups in STEM. Collaborative endeavors with local communities facilitate a comprehensive exploration of the historical record, actively engaging with the present. This initiative extends beyond academia, aiming to impact agricultural practices and to facilitate knowledge dissemination. Outreach initiatives encompass students from diverse academic levels, from high school to graduate studies, providing them with a unique opportunity to immerse themselves in the realm of plant genomics. The project provides empowerment within diverse communities, offers educational opportunities to the scientists of the future, and establishes a link between the present and the prehistoric past. Researchers analyze ancient maize macrofossils spanning 1,500 years to elucidate maize evolution and diversity including adaptation to extreme altitudinal gradients. By tracing highland and lowland genes and trait selection based on human occupational periods, the research offers unique insights into the co-evolution of humans and maize, answering questions about cultivar dispersal and the impact of social events on maize genetics. The project's methodology compares ancient DNA from radiocarbon dated maize fossils with modern maize, aiming to unravel how human group movement influenced maize genomics today, advancing our understanding of human-maize relationship. The research team is assembling and sequencing a diverse set of modern maize specimens that will be used as a comparative baseline sample by which to compare the ancient specimens. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.