( ver farmers in Mexico are allowed to g...)Genetically modified maize not found in southern Mexico

Over the two-year study, the researchers gathered more than 153,000 seeds from 870 maize plants in 125 fields in Oaxaca . They sent these seeds to two commercial companies in the United States that can test for very low concentrations of transgenic material in maize seeds.

The researchers were looking for traces of two key transgenes ?one or both of which are found in all GM maize crops. Test results showed no evidence of the presence of either transgene from any of the seeds.

"We now know that transgenic maize isn't growing in Oaxaca ," Snow said. "Mexican farmers who don't want transgenes in their crops will be relieved to find out that these uninvited genes seem to have disappeared."

Transgenes that were present in Oaxaca prior to this study simply may not have survived, Snow said. Modern GM varieties may not be very hardy in Oaxaca, even if they can mate with local plants and gain a degree of hardiness that way.

"Indigenous maize grows mainly in the mountains ?the climate and soils can be pretty harsh there," she said. "Also, the influx of transgenic seeds may have declined if farmers became aware of the issue and took extra precautions with their seed stocks."

The Mexican government might approve the cultivation of GM maize at some point in the future ?meanwhile, transgenic seeds can easily enter Mexico from the United States, and more cases of wandering transgenes seem likely.

Snow conducted the work with scientists from the Instituto Nacional de Ecologia (SEMARNAT) and the National Commission for the Knowledge and Use of Biodiversity (CONABIO), both in Mexico City; and from Genetic ID North America, Inc., in Fairfield, Iowa.