"Worst ever" contamination of Mexican landraces.

• Author: Ho, Mae-Wan
• Position: Biodevastation - Brief Article

A senior Mexican Government official added fuel to the maize war by announcing results of investigations by its own scientists. The announcement was made on April 18, during the Biodiversity Convention meeting in the Hague. Jorge Soberon, senior civil servant and the executive secretary of Mexico's national commission on biodiversity, said government tests have now shown the level of contamination was far worse than initially reported.

Ignacio Chapela and David Quist of the University of California at Berkeley ignited a controversy when they reported contamination of Mexican land-races growing in remote regions.

The government went on to take samples from sites in two states, Oaxaca and Puebla, said Ezequiel Ezcurra, the director of the institute of ecology at the ministry of the environment in Mexico. The states are the genetic home of maize.

A total of 1,876 seedlings were collected, and evidence of contamination was found at 95% of the sites, when screened for the cauliflower mosaic virus (CaMV) 355 promoter. Contamination varied from one to 35% of the crop plants, with 10--15% average.

Mr Soberon confirmed that this infiltration of supposedly pure strains was the worst recorded anywhere. The worst contamination was found near main roads, along which maize is sold to villagers. In remote areas, contamination was down to 1-2%.

Biotech giants Monsanto, Syngenta and Aventis all make transgenic crops with the CaMV promoter. In order to identify the source of the contamination, it is necessary to know the detailed structure of the transgenic insert and its location in the plant genome. Unfortunately, such "eventspecific" molecular data, if they exist, are hidden from the public under "commercial confidentiality" and they refuse to give the information out.

"I find that extremely difficult to accept," Soberon said. "How can you monitor what is going on if they do not allow you the information to do it?"

This was one of the main issues raised in the Biosafety meeting that followed, during a protracted discussion on the level of information that must accompany a shipment of GMOs. Dr. Tewolde Igziabher, Head of the African Region, and delegate from Ethiopia, insisted on the importance of supplying full information, referring to the serious contamination of Mexican maize.

The delegate from Australia rebutted Tewolde's statement by telling the conference that Nature had retracted the paper, giving the impression that the science was suspect and the...