Alarming Effects Of
Genetic Plant
Manipulation Discovered
By Jeff Barnard
(AP) - Heightening environmentalists' fears about the dangers of genetic engineering, a weed that was altered by scientists to resist a herbicide also developed far greater ability to pollinate other plants and pass its traits on.
The findings raise the possibility of the emergence of "superweeds'' impervious to weedkillers.
The weed's enhanced ability to pollinate other plants was an unintended consequence of experiments with Arabidopsis thaliana, a species commonly used in genetic research.
Joy Bergelson, a professor of ecology and evolution at the University of Chicago, said the findings show that genetic engineering can substantially increase the chances of "transgene escape,'' or the spread of certain traits from one plant to another.
Her study was published in Thursday's issue of the journal Nature.
Charles Margulis of Greenpeace said the results confirm fears that genetically engineering cotton and soybeans to survive spraying with herbicides to make weed-control easier will force farmers to spray heavier doses of herbicides or use types that are less environmentally safe.
"It's just another chink in the armor of the industry, which keeps saying environmentalists' claims of health concerns just aren't justified,'' Margulis said.
Scientists have already recognized that when a genetically engineered crop grows near a weed relative, the gene-engineered trait will eventually transfer to the weed.
In a separate study, Ohio State University scientist Allison Snow found that when weeds acquire herbicide resistance from genetically engineered crops, they maintain their ability to pass these traits on, rather than becoming less fertile, as some had believed.
Ms. Bergelson compared the fertilization rate of plants that were mutated to make them resistant to the herbicide chlorsulphuron, and plants that were genetically altered for the same trait.
The genetically altered plants were able to fertilize other plants at a rate 20 times greater than that of the mutants.
Why this was so is not clear. Ms. Bergelson speculated that the pollen from the genetically altered plants might have a longer lifespan than normal pollen or have some other competitive advantage.
Ms. Bergelson's findings do not raise any fundamental new issues for companies developing genetically engineered plants, said Rob Horsch, vice president and general manager of the Agracetus Campus of Monsanto Co. in Middleton, Wis. The government already has stringent controls.
"The possibility of outcrossing has always and will always exist, and none of the regulatory decisions or safety analyses that I'm familiar with depend on arguments about the frequency of cross-pollination itself,'' Horsch said.