Science in Society Archive

"Worst ever" Contamination of Mexican Landraces

Senior Mexican Government official adds fuel to maize war by announcing results of investigations by its own scientists. But denial and obfuscation continue. Dr. Mae-Wan Ho reports from her recent visit to the Biosafety Conference at The Hague.

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 with the cauliflower mosaic virus (CaMV) 35S promoter. Contamination varied from one to 35% of the crop plants, with 10-15 per cent 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 between 1 and 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 'event-specific' molecular data, if they exist, are hidden from the public under 'commercial confidentiality' (see "Astonishing denial of transgenic contamination", this series), 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 problem does not exist. Australia is part of the Miami group of nations around the United States, a non-party of the Biosafety Protocol that nevertheless has been allowed to dominate all the negotiations. But the signs are that even the Miami group is breaking up, and the United States is finding itself increasingly isolated.

Fortunately, I had anticipated this would be a key point of contention, and had written a short explanatory note for circulation to all the delegates. I intervened, pointing out that the scientists were not disagreeing over the fact that transgenic contamination had occurred. Rather is it the finding that the transgenic construct appears to have fragmented into pieces on entering the land races' genome that is disputed. The only way to settle the dispute is to have 'event-specific' molecular data My intervention brought an immediate response from Val Giddings, of the US industry group BIO, who said that the Nature paper was not retracted, it was "rebutted". To which I invited delegates to read another report I circulated (see "Astonishing denial of transgenic contamination", this series).

Many delegates thanked me afterwards, and asked for more information. At least some of them were under the impression that the same gene in different crops will give the same genetic modification.

The last thing industry wants is to have to provide 'event-specific' molecular data, for fear of exposing the transgenic lines to be genetically unstable in the first place. So, they are trying to obfuscate the issue and divert attention away from molecular data.

The Organisation for Economic Co-operation and Development (OECD) - the club of rich countries - known for its pro-GM stance, tabled a document at the Conference, OECD Guidance for the Designation of a Unique Identifier for Transgenic Plants. This document was supposed to offer a solution to the overwhelming demand for specific information on GM imports from the exporting countries. But the "unique identifiers" turn out to be utterly irrelevant for biosafety. They are merely keys for accessing information stored in the Biosafety Clearing House, an electronic scientific database on crops commercially approved, the nature of which is also much in dispute. I circulated yet another note to the delegates warning them of the OECD ploy ("Insist on 'event-specific ' molecular data! The 'unique identifier' for biosafety is 'event-specific' molecular data", I-SIS members' website.).

Article first published 29/04/02

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