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Who’s Watching the Greenhouse?

The uncertainty is due, in part, to the lack of a rigorous regulatory framework to sort out the risks inherent in agricultural biotech. The plastic cages covering the heads of the sunflowers help keep the transgenic pollen out of the environment, a general requirement for obtaining a federal permit to grow a test crop of bioengineered plants. But other than monitoring the plots, the government imposes few conditions on biotech tests. The main reason is that Congress has not passed any specific environmental law for genetically engineered agriculture. Instead, transgenic crops are evaluated by three overlapping federal agencies: the Food and Drug Administration, the Environmental Protection Agency, and the Department of Agriculture.

Each government agency has a different statutory responsibility, which sometimes leads to anomalies-and gaps in regulations. The FDA, for example, doesn’t look at the safety of foods that have been engineered to express pesticides, because pesticides are by law exempt from the agency’s purview. Nor does the EPA, which is required to treat such foods as pesticides. Because pesticides, of course, are toxic substances, the agency only establishes human “tolerances” for each compound. (Responding to critics’ concerns, the agency announced this spring that it may rethink its approach.) For its part, the USDA simply tries to make sure that the crop grows in the way that the manufacturer says it will. The disjointed legal mandates, observes EPA biotechnology adviser Elizabeth Milewski, “make life interesting.”

One worrying consequence of this patchwork of regulations is that no one has direct responsibility for looking at long-term effects on the environment. “We have a first-approximation understanding of the population biology of these plants and the insects, microbes and virus populations,” says Neal Stewart, a biologist at the University of North Carolina at Greensboro. “But we know very little about the community ecology and virtually nothing about the ecosystem ecology of what these genes will do. And we are not pursuing this knowledge actively.” Stewart’s concerns bore fruit in May, when Cornell scientists reported that pollen from Bt corn can kill the caterpillars of monarch butterflies.

According to Sally McCammon, science adviser to the USDA Animal and Plant Health Inspection Service, biotech field trials can be of any size and last for any length of time, though one or two years is the standard. From the companies’ point of view, the tests are efforts to learn whether new crop varieties will perform as intended. The government’s main job, McCammon says, “is to certify that the test is biologically contained.” Transgenic plants must be kept apart from plants they might cross-pollinate. “Afterwards you have to account for it,” McCammon says. “We make sure that you bag what you take out and that the plant material is plowed under.”

These measures are necessary, to Snow’s way of thinking. But by ensuring that transgenic genes won’t escape into the environment, they also make it impossible to learn what will happen if they do. “The ecological questions don’t even get touched,” she says. “In fact, it’s illegal to touch them.” She believes that the environment and industry would be better served by introducing a second level of testing devoted to ecological questions. Another step, in her view, would be to fund academic research into the ecological hazards-currently the sole source of federal funds, the biotechnology-risks panel of the USDA, has a budget of less than $2 million.

Technical controls may also be possible, says Gressel of the Weizmann Institute. Most transgenic crops today have a single foreign gene. But companies are already working on inserting several genes simultaneously into the plant’s genome. In a May article in the journal Trends in Biotechnology, Gressel argues that if these multiple genes were inserted in close proximity to each other on the chromosome, potential hybrids would inherit all of them at once. And if the secondary genes coded for traits such as preventing dormancy, the hybrids would be less, not more, dangerous than their wild parents. For crops, the inability to lie dormant doesn’t matter, because the seed is harvested and replanted each year. But a weed that is unable to produce seed that can remain dormant until an opportune time to germinate is at a significant disadvantage. “The hybrid weed will be weaker, not stronger,” Gressel says.

“I’m more worried about the future than the present,” Ellstrand says. “So far it’s okay-we don’t have killer tomatoes flying through the air. But we need to be thoughtful and careful about what we’re doing, and there are some people and some portions of the industry where they have a better tradition of that than others. People who have worked with plants outside in real life seem to have a better handle on it than people who have worked with chemicals all their life. If we keep paying attention to what’s happening in the field, we might be able to make this technology realize its promise.”

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Tagged: Computing, Biomedicine

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