Genetically modified foods: breeding uncertainty

Environmental Health Perspectives, August, 2005 by Charles W. Schmidt

Genetically modified (GM) crops first appeared commercially in the mid-1990s to what seemed a bright and promising future. Resistant to pests and the herbicides used to control weeds, these new crops were so popular with farmers that millions of acres were planted with them by the turn of the millennium. Today, GM crops are grown commercially by 8.25 million farmers on 200 million acres spread throughout 17 countries, reports the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), an international nonprofit that advocates for the technology. The world's top five producers--the United States, Argentina, Canada, Brazil, and China--account for 96% of global GM cultivation; of this, more than half is in the United States.

Yet these impressive numbers tell only part of the story. Fully as notable as the growth of GM agriculture is the relentless backlash that has developed against it. Although GM supporters insist the technology raises harvest yields, reduces agrochemical use, and will eventually even produce high-nutrition food that can grow in depleted soils, skeptics counter that the risks of GM foods--made with gene splicing methods from biotechnology--are unknown and poorly addressed by current testing methods. They also worry that the spread of GM crops, which are supplied mainly by a handful of multinational companies, fuels corporate ownership of the seed supply and threatens the purity of indigenous crops, with which GM varieties can breed by cross-pollination.

A Growing Backlash

The opposition's attacks are generating sustained impacts. In April 2004, biotech companies including Novartis Seeds, Aventis CropScience, and Bayer CropScience abandoned GM field trials in England, citing challenges raised by British consumers. The next month, Monsanto dropped its new variety of herbicide-resistant wheat despite hundreds of millions reputedly spent on research and development. The product was shelved in part because of threatened boycotts by Europe and Japan, which together buy 45% of all U.S. wheat exports, according to the U.S. Department or Agriculture Economic Research Service (UDSMERS). And in November 2004, the world's largest agrochemical company, the Swiss-based Syngenta, moved its European GM field trials to the United States, also citing public resistance.

Europe itself, where commercial GM crops are grown only in Spain--and there in small amounts--is politically gridlocked over the issue, says Geoffrey Lean, environment editor for The Independent on Sunday, a British newspaper. The European Commission lifted a six-year moratorium on GM food in Europe last year, but even so, no new crops have been granted entry, he says. The commission, which favors the technology, wants to allow more GM imports. However, a number of opposing countries--notably Austria, France, Portugal, Greece, Denmark, and Luxembourg--have so far prevented this from happening. "As far as opinions in Europe go, the public is heavily against GM, the scientific community is for it, and governments are split down the middle," Lean says.

Developing countries are also heavily divided, even though they could arguably benefit the most from the technology. Some stakeholders worry that the introduction of GM seed in developing countries could threaten the purity of conventional crops, thus posing a risk to food exports bound for markets that reject the technology.

Meanwhile, a slew of "GM-free zones," where all transgenic organisms are banned (including fish, other animals, and plants used to make drugs), are cropping up around the world. Three are in the United States, all in California. More than 3,000 are found throughout Europe, with others in Canada, Australia, and the Philippines, says Renata Brillinger, director of the citizens group Californians for GE [genetically engineered]-Free Agriculture.

GM crops also suffer a poor reputation among the general public, in part because they are made in ways that can sound scary when described to consumers. Biotechnology allows scientists to combine genes from totally unrelated species of plants, microbes, and animals. How is this possible? There are several methods. In one, bacteria and viruses--which are naturally able to penetrate cells--are deployed as delivery vehicles to shuttle genes directly into plant cell genomes. In another, tiny particles coated with a gene are propelled at high speeds into cells to deliver the gene. In still another, electric shocks are used to destabilize cell membranes, making them permeable to delivered genes. These and several other methods enable scientists to evade natural barriers that cells use to protect themselves from foreign DNA.

Thus, genes from bacteria can be introduced into a plant--or, as in one instance, a fish gene can be introduced into a tomato. Monsanto has made pest-resistant varieties with a gene from Bacillus thuringiensis (Bt), a bacterium that kills certain types of insects. The resultant varieties produce the Bt toxin, a protein that is lethal to these insects but safe for humans. DNA Plant Technology of Oakland, California (which has since gone out of business) was the company responsible for inserting a fish gene into a tomato. In that case, an "anti-freeze" gene that helps flounder survive frigid waters was spliced into tomato cells to enhance the plant's resistance to cold. The fish-tomato didn't swim, nor did it ever make it to market. But its memory lingers as a quintessential "frankenfood" that GM critics often refer to.