Evidence for Multiple Teosinte Hybrid Zones in Central Mexico

Abstract

1O_LIHybrid zones provide an excellent opportunity for studying population dynamics and whether hybrid genetic architectures are locally adaptive. The genus Zea contains many diverse wild taxa collectively called teosinte. Zea mays ssp. parviglumis, the lowland progenitor of maize (Zea mays ssp. mays), and its highland relative Zea mays ssp. mexicana live parapatrically and, while putative hybrids have been identified in regions of range overlap, these have never been deeply explored. C_LIO_LIHere we use a broadly sampled SNP data set to identify and confirm 112 hybrids between Zea mays ssp. parviglumis and Zea mays ssp. mexicana, mostly clustered in three genetically and geographically distinct hybrid groups in Central Mexico. C_LIO_LIThese hybrid groups inhabit intermediate environments relative to parental taxa. We demonstrate that these individuals are true hybrids and not products of isolation by distance or ancestral to parviglumis and mexicana. This work expands on previous studies, clearly identifying hybrid zones in Zea, genetically characterizing hybrid groups, and showing what appear to be unique genetic architectures of hybridization in distinct hybrid groups. C_LIO_LIWith the potential for local adaptation, variable hybrid zone dynamics, and differential architectures of hybridization, we present these teosinte hybrids and parental taxa as a promising model system for studying hybridization and hybrid zones. C_LI