Early origins of maize in Mexico( The ancestors of maize originally grew ...)

The ancestors of maize originally grew wild in Mexico and were radically different from the plant that is now one of the most important crops in the world. While the evidence is clear that maize was first domesticated in Mexico, the time and location of the earliest domestication and dispersal events are still in dispute. Now, in addition to more traditional macrobotanical and archeological remains, scientists are using new genetic and microbotanical techniques to distinguish domesticated maize from its wild relatives as well as to identify ancient sites of maize agriculture. These new analyses suggest that maize may have been domesticated in Mexico as early as 10,000 years ago.

Dr. John Jones and his colleagues, Mary Pohl, and Kevin Pope, have evaluated multiple lines of evidence, including paleobotanical remains such as pollen, phytoliths, and starch grains, as well as genetic analyses, to reconstruct the early history of maize agriculture. Dr. Jones, of the Department of Anthropology, Washington State University, Pullman, will be presenting this work at a symposium on Maize Biology at the annual meeting of the American Society of Plant Biologists in Mrida, Mexico (June 28, 8:30 AM).

While macrobotanical remains such as maize kernels, cobs, and leaves have been found in dry mountain caves, such remains are not preserved in more humid lowland areas, so the conclusions based on such remains are fragmentary. Much smaller parts of the maize plant, like cellular silica deposits, called phytoliths, and pollen and starch grains, are preserved under both humid and dry conditions. These lines of evidence, along with genetic and archeological data, are being used to reconstruct the history of agriculture to its origins around the world.

Maize is wind pollinated and sheds large amounts of pollen, which is deposited in soil and water sediments. The tough outer wall (exine) of pollen protects it from deterioration for thousand
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