Dises: coevolutionary dynamics of humans and maize in the americas

The National Science Foundation (NSF) awarded a $1,599,717 Project Grant to the University of California, Davis (UC Davis) under the Biological Sciences program (CFDA 47.074) to study the coevolutionary dynamics of humans and maize (corn) in the Americas. The 3-year grant, effective August 1, 2023, will synthesize genetic, archaeological, and linguistic data to model how the cultivation and dispersal of maize enabled human population growth and cultural change, and how human activities shaped the evolution of maize. The project incorporates an educational video game for K-12 students on the interconnected histories of humans and maize. As part of the grant, UC Davis is collaborating with the Swedish University of Agricultural Sciences (Sveriges Lantbruksuniversitet) to leverage their expertise in ancient DNA analysis and demographic modeling of maize.

Abstract

Corn, or maize, originated in the americas but is now the most productive crop in the world, used for food, animal feed, fuel, and industrial manufacturing. Unlike some cultures that cultivated a broad array of staple crops, many indigenous peoples in the americas relied primarily on maize. The survival and growth of many human populations and economies in the americas was tied to the success of their maize crop, and many indigenous origin stories even posit that humans were literally created from maize. In turn, maize population growth and dispersal were dependent on human cultivation, and the modern maize form is the result of thousands of years of human selection for dietary, cultural, and economic needs. An interdisciplinary team of geneticists and archaeologists will synthesize publicly available data on humans and maize in the americas and develop and apply novel analytical approaches to understand their entwined history. Previous studies of the relationship between humans and their domesticated plants and animals have been largely one-sided, but the approaches developed in this project will provide other researchers the tools to explicitly study the interactions driving such systems. These events occur and will be studied in the context of changing environments. Researchers will incorporate these interdisciplinary approaches into an educational video game for k-12 students that includes lessons on genetics, archaeology, and botany. The project will combine existing approaches with newly developed methodologies for CO-estimating dispersal and demographic shifts to build CO-evolutionary models and test specific a priori hypotheses about the evolution of humans and maize. Combining population genetics with archaeological data, researchers will reconstruct histories of admixture and population size change to how maize enabled human population and cultural change and how human movement and economic exchange patterned the dispersal of maize. Phylogenetic comparison of indigenous linguistic data to maize genetic data will further evaluate the impact of human culture and economy in patterning maize diversity, and researchers will use additional genetic, archaeological, and morphological data to test hypotheses about reciprocal cultural and genetic changes in each species. 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.