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Evidence of threat from GM crops mounts, says director of labeling campaign by Craig Winters
(Aug. 16, 2002 -- CropChoice guest commentary) -- Evidence continues to mount that genetically engineered foods pose a
threat to both human health and the environment. The grocery industry
and government officials are probably beginning to wonder if they have
been mislead by the agricultural biotech industry about the safety of
these crops.
In July, concerns about the health effects of genetically engineered
foods were raised after a report was issued by the United Kingdom's Food
Standards Agency. That report indicated that the DNA from genetically
engineered soy was found to have transferred to bacteria in the human
gut. The biotech industry had long promised that the genetically
engineered DNA would be broken down during the digestive process and not
transfer to bacteria in the human body.
Research on rats has shown the genetically engineered DNA is also
transferring to their blood cells. This "horizontal gene transfer" is
also likely happening in human blood cells. But no human feeding studies
are being conducted, except for the massive uncontrolled one that is
taking place on American consumers who are eating unlabeled, untested
genetically engineered foods. No one knows what the long term health
effects will be of feeding humans genetically engineered foods.
Now two studies have been released that show genetically engineered
crops may be contributing to the creation of "superweeds." Biotech
industry scientists originally said this would not happen because the
chromosomes are so mismatched. But now they are finding that viable
offspring are being created.
I've included below two stories. The first article titled "Scientists
shocked at GM gene transfer" is from the British newspaper The Guardian.
The second article is from the Environment News Service and titled
"Engineered Genes Help Wild Weeds Thrive."
Perhaps what is most disturbing about learning that genetically
engineered DNA is transferring in the human body and into weeds in the
fields is that we are just discovering this now. There are currently over
80 million acres of these risky crops growing in the United States.
Shouldn't this research have been done before we allowed these genetically
engineered crops to be planted?
1. Scientists shocked at GM gene transfer
Paul Brown, environment correspondent
Weeds have become stronger and fitter by cross-breeding with genetically
modified crops, leading to fears that superweeds which are difficult or
impossible to control may invade farms growing standard crops.
Two separate teams, one working on sunflowers in the US and the other on
sugar beet in France, have shown weeds and GM food crops readily
swapping genes.
In the case of wild sunflowers, classed as "weed" varieties in America,
specimens became hardier and produced 50% more seeds if they were
crossed with GM sunflowers which had been programmed to be resistant to
seed-nibbling moth larvae.
Allison Snow, who headed the team at Ohio State University, confessed in
New Scientist that she was "shocked" by the results. "It does not prove
all GM crops are dangerous," she said. "I just think we need to be
careful because genes can be very valuable for a weed and persist for
ever once they are out there."
Pioneer Hi-Bred, which developed the GM sunflower, has abandoned the
idea of selling the strain commercially.
The sugar beet results show that wild and GM varieties swapped genes,
sometimes to the advantage of the wild varieties and the detriment of
the GM plants, which produced lower yields. Writing in the Journal of
Applied Ecology, the University of Lille team said they had
underestimated the likelihood of GM beets swapping genes with the beet
weeds that grow among them.
The two sets of results add to the fears of environmental groups and
organic farmers that normal crops could be contaminated by GM varieties
- and make weeds impossible to control. This is less of a problem in
countries where crops have been introduced, for instance soya grown the
US, because no native weed varieties exist. But in Europe, particularly
in Britain, where weed species of both beet and oil seed rape exist, the
risk is potentially serious.
Adrian Bebb, GM campaigner at the environmental group Friends of the
Earth, said GM beet was now being grown at 16 farm-scale trial sites in
England. "Once again scientists are discovering new impacts of GM
crops," he said. "The government always emphasises the importance of a
sound scientific approach to GM crop safety, so they should look at this
research seriously and question whether or not we should be testing GM
crops out of doors."
Two years ago government research reported that GM crops could
cross-pollinate with ordinary crops over larger distances than had been
thought. The government is in its final year of trials to investigate
the effect of growing GM crops on the countryside.
2. Engineered Genes Help Wild Weeds Thrive
By Cat Lazaroff
WASHINGTON, DC, August 9, 2002 (Environment News Service ) - For the
first time, researchers have demonstrated that foreign genes from a
genetically engineered crop plant can migrate into wild plants in a
natural environment. A study released Thursday shows that wild weeds can
incorporate bioengineered genes, potentially making the weeds stronger
and more resistant to pests.
Scientists from three universities studied genetically engineered
sunflowers - those modified with a gene that produces a chemical toxic
to certain insects - to see what happened when these foreign genes,
called transgenes, were inadvertently passed along to weedy relatives.
"This is the first example of what might happen if a beneficial
transgene accidentally spread to a wild population and then proliferated
in subsequent generations," said Allison Snow, a study co-author and a
professor of evolution, ecology and organismal biology at Ohio State
University.
The team studied hybrid sunflowers containing a transgene from the soil
dwelling bacterium Bacillus thuringiensis that produces chemicals toxic
to certain insects. The Bt toxin gene has been added to a number of
commercial crops, including corn, cotton and soybeans, to help the
plants repel moths and butterflies, whose larvae are prime predators of
growing crops.
The researchers crossbred cultivated sunflowers containing the Bt
transgene with wild, non-Bt sunflowers. The experimental populations
were grown at two sites - an open, pasture like area in Nebraska and an
intensely cultivated area in Colorado.
The second generation of wild sunflowers contained the transgene,
showing that the alien gene could be transferred. The researchers then
concentrated on learning what effects the new gene would have on the
wild sunflowers.
The wild Bt sunflowers had 50 percent more seeds than control hybrids
without the gene. These plants also had far less insect damage,
suggesting that that the insecticidal gene was working by preventing
insects from eating the plant.
"We were surprised that a single transgene could have such a big effect
on seed production," Snow said. "A plant with a transgene may have to
divert more energy to handle this new compound it's making. Doing so
could reduce the plant's ability to reproduce. But that certainly wasn't
the case here."
The researchers also found that the addition of the Bt gene did not harm
the weeds' physical fitness, even when the sunflowers were deprived of
water and nutrients to mimic drought conditions.
"There were no costs at all to inheriting the transgene," Snow said.
In many crop species grown commercially in the U.S., wild relatives will
readily crossbreed with crops growing nearby. Such unions happen in more
than 20 species in the United States, including sunflowers, sorghum,
carrots, radishes, rice and turf grasses.
Most of these crops have not yet been modified to carry insect fighting
transgenes in their DNA. But as more crops are modified to resist pests,
the risk that the alien genes will end up in the environment is growing.
"Many genetically modified cultivated crops could potentially crossbreed
with weeds," Snow said. "Weeds are already hardy plants; the addition of
transgenes could just make them tougher."
One possible outcome of the Bt gene transfer would be a population of
"super weeds," able to resist insect damage more readily than unaltered
varieties.
In other cases, exposure to engineered genes could make weeds resistant
to herbicides used to control weed growth around crops. Certain crops,
particularly soybeans, have been engineered to resist certain
herbicides, allowing farmers to spray both crops and weeds while killing
only the weeds.
If some of the weeds were to take up this gene, they could also develop
resistance to herbicides.
Bt sunflowers are not currently sold in the United States. In the
current study, to keep the hybrid sunflowers from spreading outside of
the area of the field experiments, the researchers removed all of the
non-sterile plants that carried the Bt gene. The researchers also
collected seed heads from all of the remaining Bt sunflowers before the
seeds had a chance to fall to the ground.
During the two years following the study, the experimental plots and
surrounding areas were sprayed with herbicides meant to kill wild
sunflower seedlings.
"While it's obvious that a single gene can have a huge impact on plant
reproduction in a natural setting, there are still a lot of unknown
effects, like whether or not the weed could spread at a faster rate,"
noted Snow.
She and her colleagues are continuing their research and trying to
understand if wild sunflowers with beneficial transgenes could become
troublesome weeds.
Snow conducted the study with researchers from the University of
Nebraska and Indiana University. The team presented their findings
August 8 at the annual meeting of the Ecological Society of America in
Tucson.
The research was supported by the U.S. Department of Agriculture and
seed manufacturers Pioneer Hi-Bred and Mycogen Seeds. | |
