Parallel Adaptation in Maize Landraces
Maize was domesticated in the lowlands of the Balsas River Valley in southwest Mexico. Subsequent to domestication, maize spread from its center of origin to vastly different environments. In some instances, similar new environments were occupied in parallel–for example, the cool highlands of Guatemala, the southwestern United States, the Mexican Central Plateau, and the Andes. In the context of parallel highland colonization, we are investigating two primary evolutionary questions in maize: 1) What is the evidence for local adaptation to highland conditions? and 2) Have putative highland adaptations involved a similar set of alleles and/or loci? We are currently using field and growth chamber experiments to assess evidence for local adaptation and taking a comparative genomic approach to identify candidate loci for adaptation.
Gene Flow and Introgression in the Genus Zea
Previous work has shown substantial evidence for gene flow across taxa in the genus Zea. We are interested in both the genomic architecture of isolation in regions where Zea taxa hybridize as well as the potential for adaptive introgression between these species. A particularly compelling hypothesis is that teosinte provided local adaptation to maize through gene flow and introgression during its post-domestication spread across Mexico and Central America.