Study Claims to have Found Transgenes in Mexican Maize

Scientists at the National Autonomous University of Mexico (UNAM) have detected transgenes from genetically modified maize in traditional Mexican landrace varieties, says a news article published by the journal Nature. The study echoes a similar, controversial work published by the prestigious journal in 2001. Scientists from the University of California, Berkeley found traces of genetically modified maize in wild varieties of the crop. The UC Berkeley article caused a storm of controversy and was disowned by Nature saying that “there was insufficient evidence to justify the original publication.” Critics pointed out some technical errors in the experiment, including problems with the type of polymerase chain reaction used to amplify the DNA sequences.

The scientists from UNAM tested seed and leaf samples for the presence of the 35S cauliflower mosaic virus, and the nopaline synthase terminator, NOSt. The team found transgenes in about 1 percent of more than 100 fields it sampled, including some sampled by the UC Berkeley researchers. The Nature news article, however, noted that the study failed to confirm an important conclusion made by the UC paper - whether the transgenes had been integrated into landrace genomes and passed along to progeny plants.

The article was recommended for publication to the Proceedings of the National Academy of Sciences (PNAS) but was rejected. The study will be published in the journal Molecular Ecology.

The news article published by Nature is available at http://www.nature.com/news/2008/081112/full/456149a.html#B1