About GM crops - 未名空间MITBBS历史存档

k*n2011-01-06 08:01

1 楼

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B*n2011-01-06 08:01

2 楼

Anyone has inside information on this issue ?
http://www.gmwatch.org/component/content/article/11573-gm-indus
In the US, under the Federal Food, Drug and Cosmetic Act of 1938, the FDA is
responsible for ensuring that food is safe to eat, although by statute, it
regulates only food additives. By that definition, most crops are exempt
from FDA approval, although companies tasked with ensuring their products
are safe often voluntarily submit a considerable amount of information.
Certain types of commercialized crops also fall under the jurisdiction of
the USDA and the EPA: the USDA is concerned with minimizing gene flow, the
EPA regulates crops containing pesticides, such as those with insect-
resistance traits. Transgenic and conventional crops with other traits -
herbicide tolerance or nutritional enhancement - could enter the marketplace
with almost no review of the potential health impacts1. The EPA also
regulates unintended effects on nontarget insects, although a review of
published studies identified problems that limit their usefulness2,3. The
fact that much of the data submitted to regulatory agencies remains
confidential business information that is not shared with the research
community means that for many crops (transgenic or otherwise), little
information on human or environmental toxicity is known. Certainly, there is
a paucity of such studies in the literature. Spanish researcher Jose
Domingo, at Rovira i Virgili University in Reus, conducted a literature
review of toxicity studies conducted on commercialized GM crops. So few
research papers turned up in his search that he asked, "Where is the
scientific evidence showing that GM plants/food are toxicologically safe?"4.
In some instances, university scientists have raised concerns about data
submitted to regulatory agencies, but had no recourse. In 2001, for example,
Pioneer was developing a transgenic corn variety that contained a binary
toxin, Cry34Ab1/Cry35Ab1, to fend off rootworms. The company asked some
university laboratories to test for unintended effects on a lady beetle. The
laboratories found that nearly 100% of lady beetles that had been fed the
crop died after the eighth day in the life cycle. When the researchers
presented their results to Pioneer, the company forbade them from
publicizing the data. "The company came back and said ‘you are under no
circumstances able to publicize this data in any way’," says a scientist
associated with the project, who asked to remain anonymous. Because the
product had not yet been commercialized, the research agreement gave Pioneer
the right to prevent publication of their results.
Two years later, Pioneer received regulatory approval for an antirootworm
corn variety with the same toxin—Cry34Ab1/Cry35Ab1. But the data submitted
to the EPA had no sign of potential harm to lady beetles, even though
Pioneer had followed common EPA testing protocols. In one study, the company
fed purified toxins to the lady beetles only through the seventh day of
their life cycle - one day short of what was found to be their most
susceptible stage. In a second study, the company followed the lady beetles
through the end of their life cycle but used a different mode of feeding,
through a homogenized powder consisting of half prey and half pollen, and
didn’t see any effect, according to Jim Register, a scientist at Pioneer.
Register also says that although Pioneer’s commercialized product contains
the same toxin as the one the universities studied, it is a different
construct—key genes were integrated into a different place in the genome.
The anonymous researcher maintains that Pioneer's studies are flawed. The
EPA was made aware of the independently produced data, but opted not to act,
according to the anonymous source. Pioneer would also not give the
scientists permission to redo the study after the crop was commercialized.