Genetic contamination in Mexican maize

2001/11/29 Elhuyar Zientzia

• Botanika
• Genetika
• Osasuna

Genes that have been introduced into GM rye have been found in wild Mexican maize varieties. Researchers at the University of California have detected this genetic contamination and have published this data in the journal Nature today.

Experts have greatly surprised this result, especially by the implementation in Mexico of a moratorium against genetically modified products since 1998, and have stressed the importance of avoiding the spread of transgenic DNA. Genetic contamination is normal.

Previously, the National Institute of Ecology of Mexico and the National Commission on Biodiversity had conducted such an investigation with similar results, although they had not been published. According to them, 10% of wild maize seeds contained transgenic DNA.

The foreign DNA detected in these maize varieties contains the gene encoding the Bt toxin (cry1Ab gene), as well as the virus promoter sequence that produces a mosaic disease in the skin (the promoter is only used for transgenic corn to express the Bt toxin). This toxin is a typical toxin produced by the bacterium Bacillus thuringiensis that when integrated into the genome of the plant behaves like an insecticide.

What remains to be clarified is the origin of transgenic DNA, which was established more than 100 km from those who have discovered contaminated by transgenic rye planted in Mexico before 1998. Although it is difficult to assess the influence that foreign DNA reception may have, it is an issue that has sparked debate among experts. At least it will be a factor to consider when granting authorization for the planting of transgenic plants.