NSF Postdoctoral Fellowship in Biology: Human Domestication of Maize as Bio-cultural Coevolution

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2023. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Samantha Snodgrass is "Human Domestication of Maize as Bio-cultural Coevolution".

The host institution for the fellowship is the University of California (UC) Davis and the sponsoring scientists are Drs. Jeffrey Ross-Ibarra and Dr. Graham Coop.

Plant domestication and agriculture are key innovations underlying the past 10,000-years of human civilization. Domestication alters how plants benefit humans, which can result in tight dependencies. For example, maize cannot survive outside of human cultivation, yet is planted across the globe in extremely different environments because it is a vital food source for humans.

While archaeology and genetic research have revealed much about when and where domestication of maize occurred, it is unclear how maize was moved with and among early farmer communities and which traits were important early versus later in the process. This project uses population genetics to create methods addressing these long-standing questions in maize and other crops.

Answers may shed light on why some species are hard to domesticate and will guide efforts to domesticate new crops. Training objectives include gaining expertise in statistical population genetics, professional development for managing large, interdisciplinary teams and establishing professional ties with evolutionary biologists, anthropologists, and Mesoamerican foodway scholars at UC Davis to facilitate future collaboration.

Broader impacts include developing publicly available undergraduate curricula focused on introducing biology students to the field of population genetics and the possibilities opened by big data in both sequencing and trait-measuring efforts.

Given the close relationship between farmers and domesticates, several researchers have proposed theoretical models of domestication as bio-cultural coevolution. Current methods to investigate evolution in such systems typically focus on a single species. This project will expand upon those approaches by treating humans and maize as coevolving species.

Specifically, project objectives include 1) estimating joint admixture graphs to better understand how maize moved with and among early farmer communities and the timing and strength of selection on traits; 2) estimating signatures of polygenic selection across 200+ traits scored in maize and placing them at specific time periods within the admixture graph to show selection patterns on polygenic traits not retained in the archeological record but important to adaptation such as flowering time; and, 3) applying the results and methods to the study of other American domesticates to test the generality of domestication patterns found in maize. All scripts will be publicly available on GitHub and associated with a publication.

All genomic data will come from or be made available on NCBI and/or CyVerse and aggregated trait data will be available on a data platform such as CyVerse and/or Dryad.

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.