Bittersweet Harvest: The Debate over Genetically Modified Crops. (World in Review)

Article excerpt

In 1982 scientists on the 4th floor of the Monsanto Company U Building successfully introduced a foreign gene into a plant cell for the first time in history. These plants were genetically modified: they continued to express the new gene while exhibiting normal plant physiology and producing normal offspring. This breakthrough spawned the field of genetically modified (GM) crop production. Since the discovery, however, the international response to GM crops has been mixed. Along with the tremendous potential that lies vested in this technology, there are many risks and uncertainties involved as well. Arguments have centered on the health implications and environmental impact of cultivating GM crops and have raised disputes over national interests, global policy, and corporate agendas. Although there are many sides to this debate, discussions on GM crop regulation should be held within the context of scientific evidence, coupled with a careful weighing of present and future agricultural prospects.

Benefits and Costs

The possibility of environmental benefits first spurred the development of GM crops. The environmental issues at stake can be illustrated by one example of a potent genetic modification, the introduction of an endotoxin gene from Bacillus thuringiensis (Bt), a soil micro-organism used for decades by organic growers as an insecticide, into soybeans, corn, and cotton. These GM crops promise to reduce the need to spray large amounts of chemicals into a field's ecosystem since the toxins are produced by the plants themselves. The Bt crops pose environmental risks, however, and could possibly harm other organisms. Bt corn was shown to harm monarch butterfly caterpillars in the laboratory, although later studies performed with more realistic farming conditions found this result conclusively only with Syngenta Company's Bt maize, which expressed up to 40 percent more toxin than other brands. Another pertinent environmental issue is the possible evolution of Bt resistance in pests. Since the Bt toxin expressed by the crops is ubiquitous in the field, there is positive selection for resistance against it, which would quickly make Bt's effect obsolete. Experimentation has begun, however, that involves regulating the percentage of Bt crops in a field so that a balance can be achieved between high yields and survival of Bt-sensitive pests. Although there are still multiple layers of ecosystem complexity that need to be considered, careful scientific research can begin to address these questions.

Another potential area of risk that needs to be analyzed is the effect of GM crops on human health. A possible consequence of Bt expression in crops is the development of allergic reactions in farmers since the toxin is more highly concentrated in the crops than in the field. Furthermore, the method used to insert foreign genes into GM crops always risks manipulation of unknown genes in the plant, resulting in unforeseen consequences. The effects of GM crops on humans therefore must be tested rigorously. Fortunately, no solid evidence yet exists for adverse physiological reactions to GM crops in humans, and some scientists argue that these same genetic-modification techniques are also currently being used in the development of pharmaceutical and industrial products.

A prevailing theme in the GM debate is that when discrepancies between scientific consensus and government policy result in unwanted consequences, the blame is often placed directly on GM crop technology itself. In 2000 about 300,000 acres of StarLink corn, a Bt crop produced by Aventis CropScience, were being cultivated in the United States. Since the US Environmental Protection Agency had declared its uncertainty over the allergenic potential of StarLink, the crops were grown with the understanding that they would be used solely as animal feed. Later that year news broke that StarLink corn had found its way into numerous taco food products around the world. …


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