Genetically engineered maize in Mexico
Mexico is the centre of origin as well as a centre of diversity for maize (Zea mays). Current diversity is estimated to comprise several hundred maize varieties and landraces. The presence of transgenic maize in Mexico was first revealed through a study of scientists from the University of Berkeley, who found transgenic constructs in traditional maize varieties in Sierra Juárez in the southeast of Mexico. The findings caused great surprise because at this time there were not even small-scale field trials with transgenic maize in Mexico. Although the findings from the study were immediately attacked by industry and industry affiliated scientists, they were consistent with tests conducted by Mexican authorities. A working group of scientists commissioned by the North American Free Trade Agreement (NAFTA) as well as various other studies confirmed that the contamination of Mexican maize varieties is a reality. The NAFTA commission also concluded that maize imports from the US were responsible for the introgression of transgenic maize in Mexico. Maize was imported as food aid but was neither milled nor labelled. According to this theory, maize imported from the US was used as seed by Mexican farmers and thus found its way into traditional seed systems. A study trying to reconstruct possible ways of transgenes spreading into traditional maize seed systems found that there is still a great deal of uncertainty regarding the way transgenes have spread throughout Mexico. At least in some regions, the presence of transgenes in indigenous maize landraces is not compatible with applied models.