Final installment in a three-part series on food and the environment.
Genetically modified foods have never weighed too heavily on my mind; I figured I'd been eating them for years in sweeteners, beef, and taco shells, and I'm still healthy. Then last month I sat in on a seminar at a UC Berkeley conference on food and the environment.
Unlike the age-old traditional plant and animal breeding techniques -- in which you grab the organisms with the traits you like and mate 'em -- genetic modification involves chemically introducing genes into the chromosomes of the organism in question. With corn, the result seems pretty benign, at least to the uninitiated: GM corn looks and tastes just like, well, corn.
One problem, says Ignacio Chapela, an assistant professor at Berkeley's Department of Environmental Science, Policy and Management, is that we're still not sure how "sticky" the new genes are. We know that tiny snippets of the inserted DNA can end up in unintended places on the host chromosome, he says. Can the entire engineered package migrate around the host DNA or make the jump to other organisms? We don't know, says Chapela (see "Kernels of Truth," May 29): "We made a big bet 25 years ago to deregulate transgenic plants, and decided not to look into the risks."
The most common modified crops are designed either to thwart the European corn borer, a crop pest, or to resist glyphosate, a powerful herbicide that biotech giant Monsanto markets under the name of Roundup, selling it alongside seeds for its "Roundup-Ready" crops. By using smaller amounts of this potent herbicide on crops that can take it, the company claims farmers will cut overall herbicide use.
So is herbicide resistance so bad? Life ain't that simple, say Chapela and Greenpeace activist Jeanne Merrill. Dependence on Roundup-type systems keeps farmers beholden to large corporations for their seed. The genetic risks, furthermore, are almost completely unknown. Most importantly, they argue, the use of GM crops further narrows the genetic diversity of our food sources. GM corn strains are known to cross-pollinate between neighboring agribusinesses. What happens if all the heirloom varieties of corn around the world are so polluted?
Conference speakers also claim that Monsanto's herbicide-reduction premise is flawed. Merrill cited a May 2001 study showing that farmers growing Roundup-Ready soybeans sprayed less often, but used two to five times more herbicide with each application. And R. Ford Denison of UC Davis presented photos of Roundup-resistant weeds, suggesting that Monsanto's is a short-term solution. "We are manipulating the tree of life, but we understand very little of it," says Chapela. "Do we know what we're doing at the organismic level? No. Can we predict what will happen? No."
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