New Trait Surfaces in Altered Plant
APO 03.09.98 12:57
Copyright 1998 The Associated Press. All rights reserved.
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By JEFF BARNARD
Associated Press Writer
A weed altered by scientists to resist an herbicide also has developed far greater ability
to pollinate other plants and pass on its traits, raising the possibility of
"superweeds" impervious to weedkillers.
The findings also have heightened environmentalists' fears about the dangers of genetic
engineering.
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 today'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 experimented with a weed called Arabidopsis thaliana, a species commonly
used in genetic research.
She 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.