Among the hundreds of plants that have been domesticated in the New World, none has received as much attention or been subject to as much debate as corn, or maize (Zea mays L.), arguably the most important crop of the Americas. Controversies have existed for years over what the wild ancestor of maize is and where and when it was domesticated.
An international team of scientists led by Dolores Piperno, archaeobotanist at the Smithsonian's National Museum of Natural History, and Anthony Ranere, professor of anthropology at Temple University in Philadelphia, have discovered the first direct evidence that indicates maize was domesticated by 8,700 years ago, the earliest date recorded for the crop. The research findings will be published March 23 in the journal, Proceedings of the National Academy of Sciences.
It is certain that maize was originally domesticated in Mexico from a wild plant called "teosinte," and genetic studies of modern populations of teosinte and maize suggested this event occurred somewhere in the Central Balsas Valley region of tropical southwest Mexico. However, no research on early prehistoric human settlement and agriculture had been carried out there. Piperno and the team searched this region of Mexico for locations that showed human occupancy for the time period they thought to be critical to maize domestication, from approximately 8,000 to 9,000 years ago. They discovered sites dating to this age, excavated them and analyzed the stone tools and plant remains they retrieved. Microfossil (starch grain and phytolith) analysis from a rock shelter called Xihuatoxtla, conducted in part with Irene Holst at the Smithsonian Tropical Research provide direct evidence for the domestication of maize and a species of squash.
"Our findings confirm an early Holocene age for maize domestication and indicate that it is another important New World crop that had its origins in the tropical forest," said Piperno. "Much more w
|Contact: Michele Urie|