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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Crops that have been genetically engineered to resist herbicides can pass these genes on
to their weedier cousins, producing hybrid strains of super weeds, according to research
published in today's issue of the journal Nature.
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.
Artificially created plants, like wild plants, can breed with closely related species
to produce hybrids in what is called out-crossing.
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For example, corn, which is a grass, can cross with timothy grass, an abundant weed.
If the corn contains a gene that confers resistance to a pesticide, the resultant "weedy"
hybrid may become a pesticide-resistant nuisance that can compete with crops for water and
nutrients.
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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.
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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"It is unclear why the transgenic plants had such an abnormally high incidence of out
crossing," says Bergelson, "but the results demonstrate that genetic engineering can
substantially increase the incidence of outcrossing in a selfing species."
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Bergelson warns that the widespread use of transgenic crops may directly cause the
creation of weeds with traits intended to increase the fitness of crops, spurring a
need for new pesticides.
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