A single domestication for maize shown by multilocus microsatellite genotyping

TLDR

Maize landraces exhibit extraordinary morphological and genetic diversity, prompting some researchers to propose multiple independent domestications from teosinte. The study aims to test the multiple‑origins hypothesis for maize domestication. Phylogenetic analyses of 264 plants genotyped at 99 microsatellites were used to evaluate this hypothesis. Results indicate a single domestication in southern Mexico about 9,000 years ago, with the oldest maize types originating in the Mexican highlands and only modest post‑domestication gene flow from teosinte.

Abstract

There exists extraordinary morphological and genetic diversity among the maize landraces that have been developed by pre-Columbian cultivators. To explain this high level of diversity in maize, several authors have proposed that maize landraces were the products of multiple independent domestications from their wild relative (teosinte). We present phylogenetic analyses based on 264 individual plants, each genotyped at 99 microsatellites, that challenge the multiple-origins hypothesis. Instead, our results indicate that all maize arose from a single domestication in southern Mexico about 9,000 years ago. Our analyses also indicate that the oldest surviving maize types are those of the Mexican highlands with maize spreading from this region over the Americas along two major paths. Our phylogenetic work is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands. We also found only modest evidence for postdomestication gene flow from teosinte into maize.