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Desert Diary


Genetically modified foods are much in the news these days and highly controversial in many areas. Genetic modification of food plants by man, however, goes back many thousands of years. The ancestor of maize—corn to Midwesterners—is teosinte, which differs in only a few—but vital—ways. From individual seeds encased in an extremely hard covering, to the softly covered kernels of corn apparently is governed by only one gene. In another difference, teosinte produces side branches with male tassels at their ends, while maize has one tassel at the top and the side branches have been converted to bear female parts—again, courtesy mostly of a single gene.

The evidence indicates that selection for maize traits began in the Balsas River basin of southern Mexico some 9,000 years ago and proceeded quickly. By 6,200 years ago, small cobs had kernels so tightly held that survival likely depended on human plantings. Many thousands of years ago the major features had been selected for. Archaeological corn from New Mexico indicates selection continuing between 1 and 2 thousand years ago.
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Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.