DNA from genetically modified corn found in Mexican maize

DNA from genetically modified corn found in Mexican maize

By ALEX DOMINGUEZ, Associated Press

(November 29, 2001 1:01 a.m. EST) - DNA from genetically modified corn has been found in native corn varieties growing in remote southern Mexico, heightening fears about the dangers of bioengineered crops.

Scientists fear the accidental spread of laboratory-inserted genes could give some plants an advantage that would allow them to crowd out other varieties, reducing the world's biological diversity.

"The benefits of these crops don't outweigh the enormous risks to food security," said David Quist of the University of California at Berkeley, one of the researchers who reported the findings in Thursday's issue of the journal Nature.

Diversity is prized by scientists as a hedge against diseases, pests and climate change. While some plant strains may be vulnerable to one disease, for example, others may have natural immunity that enables them to survive.

"We can't afford to lose that resource," said Ignacio Chapela, a co-author of the study.

Four of six samples of native criollo corn taken last year from fields in Mexico's mountainous Oaxaca region were found to contain a genetic "switch" commonly used in genetically engineered plants, the researchers reported.

In addition, two of the samples were found to have another DNA segment commonly inserted by genetic engineers. And one sample contained a commonly inserted gene that prompts the plant to produce a poison effective against the European corn borer, a pest that can harm crops.

The researchers said the discovery was surprising because Mexico imposed a moratorium on genetically engineered corn in 1998. Before that, the closest government-approved plantings of such corn were at least 60 miles from the sample sites.

Scientists could not determine exactly where the foreign DNA came from. But Quist said the researchers suspect imported genetically modified corn was handed out by a government agency as food and may have been planted by recipients near their traditional crops.

They do not believe cross-pollination happened over long distances because corn pollen is heavy, does not travel far and is short-lived.

The unintended DNA mixing is not the first involving a genetically engineered plant.

Still, it highlights the need to carefully control an emerging field in which plants are being equipped with new genes to let them produce medicines and other compounds, the researchers said.

Quist said, for example, that plants are now being developed to produce compounds that act as spermicides.

"Just think if that gets out into the environment and has a negative impact on people's fertility," he said. "It's obvious there are reasons to be concerned - until we have greater information on what the impact will be - about the release of this technology."

Rebecca Goldburg of the Environmental Defense Fund said the findings show that decisions on whether to approve genetically modified plants should not be made lightly.

"I think the primary message of this article is that large-scale production of genetically engineered crops is going to have an irreversible effect because it is impossible, or virtually impossible, to contain genetic material once it is put into crops that are planted on a wide scale," she said.

Dr. Val Giddings of the Biotechnolgy Industry Organization, a trade association, said the foreign DNA in the criollo corn was not a threat to biodiversity because it would only help the strains survive. Bioengineered corn strains also help improve crop yields, lessening the need for acreage and slowing the conversion of wild areas into farmland.

"Biotechnology is alleviating the threat on biodiversity by lessening the need for land," Giddings said. "This argument that has been advanced just doesn't hold water."