After analyzing tens of thousands of seeds from maize crops grown in 2003 and 2004, researchers from Mexico and the United States found no evidence of transgenes in these indigenous varieties.
The finding surprised the researchers, said Allison Snow, a professor of evolution, ecology and organismal biology at Ohio State University . She helped lead the study that appears online this week in the Early Edition of the Proceedings of the National Academy of Sciences.
The study is the first published report to survey the frequency of transgenes in native varieties of maize. Four years ago, researchers reported finding four cobs of GM maize in Oaxaca , the southern Mexican state where Snow and her colleagues conducted their work. And despite the government's ban on planting the genetically engineered grain, other unpublished studies confirmed that GM maize had spread to remote mountain villages in the region.
In a country whose culture and identity revolve heavily around maize, or corn the crop was first developed here thousands of years ago the thought of importing GM varieties that could contaminate native plants frightens many citizens.
"The genetic diversity of native maize is an important resource with great cultural significance," Snow said. "If farmers think that their highly revered native plants have been altered by transgenes, they might even stop planting them."
"No one knew how common transgenic corn was in this area, we thought it could be as high as 5 to 10 percent," Snow said. "There is great potential for transgenes to come across the U.S. border, with millions of tons of GM grain imported each year for processed food and animal feed."