Date: 17th January 2024
Title: Admixture, alleles, and the origins of maize
Location: Seminar room 228, Lab building, Koetilantie 5
Host: Tanja Pyhäjärvi
Abstract: The widely accepted narrative of maize domestication posits a single origin from the wild grass Zea mays ssp. parviglumis in southwest Mexico, likely beginning with de novo mutation at an important gene controlling kernel architecture. However, recent genomic surveys challenge this simplicity, revealing evidence of gene flow from another wild relative, Zea mays ssp. mexicana. Here we demonstrate widespread admixture between maize and Zea mays ssp. mexicana across time and geography, suggesting a revised model of maize origins in which maize hybridized with Zea mays ssp. mexicana in the central Mexican highlands around 4000 years post-domestication. We also revisit the origin of the important domestication tga1, using population genetic analysis and simulations to show that relevant diversity at this key locus likely predated domestication, highlighting the importance of adaptation from standing genetic variation. Together, our findings challenge existing models of crop evolution and illustrate domestication as a complex evolutionary process rather than a single event.
Jeffrey's lab works on plant evolutionary genetics, with a focus on maize and its wild relatives. We use population and quantitative genomics approaches to investigate questions including local adaptation, co-evolution, and the evolution of the genome.