image: Archaeological maize cobs from the El Gigante rock shelter, Honduras. view more
Credit: Image credit: Thomas K. Harper
Ancient maize genome sequences illuminate the history of maize domestication in the Americas, according to a study. Archaeological evidence from southwestern Mexico suggests that maize domestication began there approximately 9000 years ago, with partially domesticated forms dispersing into South America by about 7000 years ago. It is unclear whether there was any subsequent backflow of domesticated maize from South America to Central America. Logan Kistler and colleagues sequenced ancient maize genomes from samples found in the El Gigante rock shelter in western Honduras. Radiocarbon dating and cob morphology suggest that domesticated maize had arrived in the area by at least 4300 years ago; the sequenced specimens date from 2300-1900 years ago. The ancient maize genomes were closely related to both ancient genomes and modern landraces from South America. The data were consistent with a second wave of maize dispersal into South America sometime during the mid-Holocene. Maize from this second wave then hybridized with established South American varieties. The presence of maize with South American ancestry at El Gigante suggests that farmers subsequently moved hybridized maize varieties from South America back to Central America around the time maize was becoming a staple crop. Such hybrids may have contributed to the development of productive maize varieties, according to the authors.
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Article #20-15560: "Archaeological Central American maize genomes suggest ancient gene flow from South America," by Logan Kistler et al.
MEDIA CONTACT: Logan Kistler, Smithsonian Institution, Washington, DC; tel: 202-633-1908; e-mail: <KistlerL@si.edu>; Douglas J. Kennett, University of California, Santa Barbara, CA; tel: 814-863-4575; e-mail: <kennett@anth.ucsb.edu>