Multiproxy evidence highlights a complex evolutionary legacy of maize in South America

Domesticatedmaize 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 domesticationcenter in Mexico and became isolated from the wild teosinte gene poolbefore traits of domesticatedmaize were fixed. Deeply structured lineages then evolved within South America out of this partially domesticatedprogenitor population. Genomic, linguistic, archaeological, and paleoecologicaldata suggest that the southwestern Amazon was a secondary improvement center for partially domesticatedmaize. Multiple waves of human-mediated dispersal are responsible for the diversity and biogeographyof modern South American maize.