Genes from genetically modified (GM) maize imported into Mexico from the United States have entered local varieties, are likely to spread, and will be very difficult to remove, according to a major report released this week.
It says that while there is no evidence that the genes pose threats to human health or the environment, action should be taken to reduce the risk of them spreading and to conserve the biodiversity of maize varieties in Mexico.
The report was released on Monday (08 November) by the North American Commission for Environmental Cooperation (CEC), which was set by the North American Free Trade Agreement and reports to the governments of Canada, Mexico and the United States.
The CEC estimates that 25-30 per cent of maize imported into Mexico for human or animal consumption is genetically modified. It warns that small-scale farmers could experimentally plant the grain that government agencies have distributed to rural communities. The resulting plants could then pollinate local varieties growing nearby.
Any genes transferred in this way could persist indefinitely if they are beneficial or neutral to the local varieties and their removal "is likely to be very difficult and may in fact be impossible", says the report.
However, it notes that it is unlikely that the transfer of a small number of individual genes have any "major biological effect" on the genetic diversity of Mexican maize. It goes on to say that transgenic maize did not appear to have any effect on other plants and animals such as insects found in Mexican maize fields, but that specific studies have still to be conducted.
The CEC's 16-member panel which includes a former executive of the Monsanto company and the chair of the American Association for the Advancement of Science made a series of unanimous recommendations.
The panel said transgenic maize imported to Mexico should be labelled, and milled at the point of entry to prevent genes from spreading to native varieties. The genetic modification of maize to produce pharmaceuticals or industrial compounds that are incompatible with food and feed should also be prohibited, they say.
Efforts to protect Mexican maize varieties should be supported, according to the CEC. To this end it recommends the development of a quality assured seed programme from which farmers could not only acquire seeds but could also have their own seeds tested for presence of foreign genes.
In a joint statement issued in response to the CEC report, the US Environmental Protection Agency and the United States Trade Representative called the report "fundamentally flawed and unscientific".