Darwiniana

Maize originated in what is now central Mexico about 9000 years ago and spread throughout the Americas before European contact. Kistler et al. applied genomic analysis to ancient and extant South American maize lineages to investigate the genetic changes that accompanied domestication (see the Perspective by Zeder). The origin of modern maize cultivars likely involved a “semidomesticated” lineage that moved out of Mexico. Later improvements then occurred among multiple South American populations, including those in southwestern Amazonia.Science , this issue p. [1309][1]; see also p. [1246][2]Domesticated maize evolved from wild teosinte under human influences in Mexico beginning around 9000 years before the present (yr B.P.), traversed Central America by ~7500 yr B.P., and spread into South America by ~6500 yr B.P. Landrace and archaeological maize genomes from South America suggest that the ancestral population to South American maize was brought out of the domestication center in Mexico and became isolated from the wild teosinte gene pool before traits of domesticated maize were fixed. Deeply structured lineages then evolved within South America out of this partially domesticated progenitor population. Genomic, linguistic, archaeological, and paleoecological data suggest that the southwestern Amazon was a secondary improvement center for partially domesticated maize. Multiple waves of human-mediated dispersal are responsible for the diversity and biogeography of modern South American maize. [1]: /lookup/doi/10.1126/science.aav0207 [2]: /lookup/doi/10.1126/science.aav7358

Source: Multiproxy evidence highlights a complex evolutionary legacy of maize in South America | Science