GM animals could threaten environment

A special committee of the US National Academy of Sciences agrees with long-time critics of biotechnology that transgenic animals could threaten the environment. Genetic manipulation of the food supply, however, is unlikely to pose serious direct hazards to human health, it said yesterday (Wednesday August 21). In a just-released report that was supposed to focus exclusively on scientific concerns about genetic manipulation and cloning of animals, the committee also touched on several policy issues. It concluded that the nation's current regulatory framework might not be equipped to deal with animal biotechnologies, especially regulations administered by the Food and Drug Administration, which requested the report. It urged labeling of genetically modified (GM) foods, a measure long opposed by industry. And it pleased animal activists by describing possible adverse effects on the health and welfare of transgenic animals. The committee said the greatest potential adverse impact of GM animals was likely to be their environmental effects, especially because it is hard to identify environmental problems in their early stages and difficult to fix them even after they have come to light. Of chief concern are insects and other animals that are hard to contain and can become feral easily, notably shellfish, fish, mice and rats. The report noted that feral cats, pigs and goats can also do serious ecological damage. The larger risk is from accidental release of transgenic organisms, although the committee said it had "a high level of concern" about intentional release as well. Escapees might spread a transgene in natural populations or they might be so much fitter that they could outcompete them. Another potential danger is an upset to the balance between predator and prey. The report said release of transgenic fish and shellfish, especially salmon, needed immediate attention. "Cultivated salmon have escaped into the wild from fish farms and these salmon already pose ecologic and genetic risks to native salmon stocks," the report pointed out. In the lab, transgenic salmon grow four to six times faster than non-transgenic salmon. According to committee member Eric M. Hallerman, a fish and wildlife biologist at the Virginia Polytechnic Institute and State University, Blacksburg, definitive studies of their fitness in the wild and their potential evolutionary consequences have yet to be done. By contrast, the committee saw little reason to think that GM food animals posed much of a health threat, with a couple of possible exceptions. Newly introduced proteins might trigger allergies or hypersensitivity reactions in some consumers. Another potential hazard is animals engineered to produce medical products in milk or eggs; the report urged strict controls to prevent carcasses of these animals from entering the food supply. The report also explored safety issues stemming from animals engineered for biomedical purposes, but drew few conclusions. It cited much-discussed but unresolved questions about transmission of disease organisms from transplanted animal organs, especially porcine endogenous retroviruses. It also noted "the theoretical possibility" that pathogenic viruses might result from recombination between a viral vector containing a transgene and normally nonpathogenic viruses in the same animal. Analogous events have been observed in the laboratory, the report pointed out. "The applications of biotechnology can have adverse effects on the welfare of animals," the committee noted, citing a number of examples. Ruminants produced by cell-culture techniques typically are bigger and have longer gestations than those produced in the usual way, which creates suffering and health problems for both mother and baby. Transgenic technologies have an exceptionally low success rate, and the animals that do result often have physical and behavioral abnormalities. Pigs intended for human transplants are raised in isolated environments that can lead to abnormal behavioral development. The committee's attention to GM animal welfare drew praise from Michael Fox, head of the Humane Society, who said he wished it had happened a decade ago.

GM animals could threaten environment

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