Maize domestication and gene interaction

The process of domestication presents a tractable system for following evolutionary change, as selective pressures shift, resulting in adaptation to the new ecological niche of cultivation. Perhaps the most detailed understanding of this process comes from Zea mays, where morphological, genetic, and genomic studies have elucidated the ancestry and selection that transformed a wild plant, the teosinte Zea mays subsp. parviglumis, into the domesticated maize Zea mays subsp. mays. These studies have identified five major morphological differences that distinguish these two subspecies, and careful genetic dissection of these phenotypes has assisted in understanding the underlying molecular genetic changes. But maize domestication was a consequence of more than just five genes, and regions throughout the genome contribute to this change. Their effects are contingent on genetic background, and the interactions between alleles and genes that give rise to phenotypes. This includes dominance relationships, epistatic interactions, and pleiotropic constraint, as well as how these variants are connected in gene networks. Together, we review the role of gene interactions in generating the dramatic phenotypic evolution seen in the transition from teosinte to maize.