In 2001 a controversial Nature paper reported that genetically modified corn ended up where none should be in the Mexican state of Oaxaca, raising concern that the transgenic varieties might invade the natural population. The journal disavowed that paper the next year on insufficient evidence, but subsequent Mexican government studies backed it. New research supports Nature’s disavowal. Mexican and U.S. researchers analyzed nearly 154,000 seeds from 870 maize plants in 125 fields over two years in Oaxaca, looking for traces of engineered genes. After expecting a transgenic presence as high as 5 or 10 percent, they were surprised to find no traces. The scientists suggest transgenic maize may not have survived in the harsh mountain climate and soil in which indigenous corn mainly grows and that local farmers may have taken extra precautions with their seed stocks after they became aware of potentially uninvited genes. The Proceedings of the National Academy of Sciences USA published the findings online August 10.
This article was originally published with the title "Missing in Maize" in Scientific American 293, 4, 32 (October 2005)