|Buckler, Edward - Ed|
Submitted to: Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/30/2005
Publication Date: 4/15/2005
Citation: Fukunaga, K., Hill, J., Vigouroux, Y., Matsuoka, Y., G, J.S., Liu, K., Buckler Iv, E.S., Doebley, J. 2005. Genetic diversity and population structure of teosinte. Genetics. 169:2241-2254. Interpretive Summary: Teosinte, a wild grass native to Mexico and Central America, is the closest wild relative of cultivated maize (Zea mays ssp. mays L.). As such, it represents an important resource for the study of maize: a thorough understanding of the evolutionary lineage and genetic constitution of teosinte can lead to reciprocal understanding for America's largest grain crop, with particular significance when applied to maize breeding strategies. In this study, the following questions were addressed: how are the teosintes related to one other, what is their population structure, and to what degree has introgression played a role in their evolution. In addition, core sets of teosinte accessions (12 or 15 out of 172 accessions) were defined that best capture the genetic diversity encompassed in the entire collection. These core sets will be a valuable resource for future research efforts that lack the time or monetary resources to assay such a large number of plants.
Technical Abstract: The teosintes, the closest wild relatives of maize, are important resources for the study of maize genetics, evolution and for plant breeding. We genotyped 237 individual teosinte plants for 93 microsatellites. Phylogenetic relationships between species and subspecific taxa were largely consistent with prior analyses for other types of molecular markers. Plants of all species formed monophyletic clades, although relationships among species were not fully resolved. Phylogenetic analysis indicated that the Mexican annual teosintes divide into two clusters that largely correspond to the previously defined subspecies: Z. mays ssp. parviglumis and ssp.mexicana, although there are a few samples that represent either evolutionary intermediates or hybrids between these two subspecies. The Mexican annual teosintes show genetic substructuring along geographic lines. Hybridization or introgression between some teosintes and maize occurs at a low level and appears most common with Z. mays ssp. mexicana. Phylogeographic analyses of the Mexican annual teosintes indicated that ssp. parviglumis diversified in the eastern part of its distribution and spread from east to west and that ssp. mexicana diversified in the Central Plateau of Mexico and spread along multiple paths to the north and east. We defined core sets of collections of Z. mays ssp. mexicana and ssp. parviglumis that capture the maximum number of microsatellite alleles for given sample sizes.