- (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.
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- The findings raise the possibility of
the emergence of "superweeds'' impervious to weedkillers.
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- 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.
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- 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.
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- Her study was published in Thursday's
issue of the journal Nature.
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- 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.
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- "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.
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- 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.
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- 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.
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- 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.
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- The genetically altered plants were able
to fertilize other plants at a rate 20 times greater than that of the mutants.
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- 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.
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- 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.
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- "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.
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