While preparing a workshop on DNA detection in Oaxaca, Mexico, David Quist found a surprise: an alien gene embedded in a sample of native corn, known as criollo. The alien was actually familiar, a type of gene commonly found in the genetically modified crops grown in the United States. Indeed, Quist observed the same DNA signature in a can of American corn he had brought for comparison. But this was an ancient strain of maize cultivated in the remote mountains of southern Mexico. How did the gene get there?
Quist and Ignacio Chapela, both microbial ecologists at the University of California at Berkeley, performed a comprehensive study of criollo in the region. Sampling four fields more than 12 miles from the closest mountain road, the researchers discovered that the native corn had incorporated not one but several genes found in engineered American corn. One sample of criollo even contained the ...
