- US scientists are warning of a potentially "serious
risk to human health" after the discovery that traditional varieties
of major American food crops are widely contaminated by DNA sequences from
GM crops.
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- Crops engineered to produce industrial chemicals and
drugs - so-called "pharm" crops - could already be poisoning
ostensibly GM-free crops grown for food, warns the study by the Washington-based
Union for Concerned Scientists, released on Monday.
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- "If genes find their way from pharm crops to ordinary
corn, they or their products could wind up in drug-laced corn flakes,"
says the report's co-author, UCS microbiologist Margaret Mellon.
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- In trials, crops have been genetically engineered to
manufacture proteins for healing wounds and treating conditions such as
cystic fibrosis, cirrhosis of the liver and anaemia; antibodies to fight
cancer and vaccines against rabies, cholera and foot-and-mouth disease.
Conventional drugs manufacture is subject to stringent controls to prevent
them entering the food chain or contaminating the natural environment.
But there are currently no such controls to prevent the spread of DNA sequences
from pharm crops.
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- The UCS asked two commercial laboratories to test traditional
varieties of three crops - maize, soybeans and canola or oil-seed rape
- for specific sequences of DNA that have been introduced into GM varieties
currently grown on US farms. The sequences studied mostly give resistance
to proprietary pesticides.
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- The labs reported that the seeds were "pervasively
contaminated with low levels of DNA sequences from GM varieties".
Up to 1 per cent of individual seeds, and more than half the batches of
seeds, contained one or more of the GM sequences.
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- Cross-pollination
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- There is no evidence that the crops tested were unsafe,
say the authors. But they fear this may not be true for second-generation
GM crops that contain DNA sequences that manufacture drugs and industrial
chemicals.
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- "Seed contamination is the back door to the food
supply," says Mellon. "The realisation that some seeds may already
have been contaminated [by pharm crops] is alarming" and could pose
a "serious risk to human health".
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- Until now concern about GM contamination has focused
on cross-pollination in the field. But the authors guess that much of the
contamination has arisen from a failure to keep GM and traditional seeds
apart during manufacture and distribution.
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- The tests did not discover any crops contaminated with
sequences from pharm or industrial crops because there are no current tests
for them. But co-author and plant pathologist Jane Rissler warns: "Until
we know otherwise, it is prudent to assume that engineered sequences originating
in any crop - including genes from crops engineered to produce drugs, plastics
and vaccines - could potentially contaminate the seed supply."
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- http://www.newscientist.com/news/news.jsp?id=ns99994709
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