by Margaret Mellon
Humble though they might seem, seeds are the foundation of the world's food supply, giving rise season after season to the plants that we and our livestock eat. Even in this era of genetic engineering, seeds cannot be assembled from scratch. They must be protected and passed on from one generation to the next.
This past February, UCS released a new report about a potential threat to our seed supply: contamination with DNA from genetically engineered organisms. This report, Gone to Seed: Transgenic Contaminants in the Traditional Seed Supply, presents the results of a pilot study UCS conducted to determine whether transgenic (genetically modified) DNA sequences from biotechnology crops adopted by the United States during the last decade could be detected in traditional (nonmodified) varieties of seeds. The study found that most of the traditional crop varieties tested were contaminated at low levels with transgenic sequences originating in genetically engineered crops.
The study tested seeds of six varieties from each of three major crops: corn, soybeans, and canola. UCS purchased the seed from the same suppliers used by U.S. farmers, and sent duplicate samples to two well-respected commercial laboratories. Using state-of-the-art molecular detection technology, the two laboratories tested the seed samples for the presence of gene sequences commonly found in genetically engineered crops.
Test Results
One laboratory detected transgenically derived DNA in 50 percent of the corn, 50 percent of the soybean, and 100 percent of the canola varieties tested. The other laboratory detected transgenically derived DNA in 83 percent of each of the three crops. Combining these results, the most conservative conclusion is that transgenically derived DNA was detected in 50 percent of the corn, 50 percent of the soybean, and 83 percent of the canola varieties tested.
Because UCS selected varieties representative of those grown by U.S. farmers, the report tentatively concludes that contamination is likely to be widespread in the U.S. seed system. Most of the specific DNA sequences for which the laboratories tested are found in popular transgenic crop varieties currently allowed on the U.S. agricultural market—primarily crops engineered for herbicide tolerance and insect resistance.
Although the study sheds little light on how the seed contamination occurred, there is no reason to believe that the transgenes detected in this study are the only ones moving into the traditional seed supply. Instead, it seems likely that seed contamination is a symptom of generally porous seed production and distribution systems. Until we know otherwise, it seems minimally prudent to assume that novel genes originating in less popular transgenic varieties, as well as the hundreds of engineered varieties that have been field tested in the United States, could potentially contaminate the seed supply of food and feed crops.
The pilot study is too limited to support quantitative estimates of overall contamination levels in seeds of traditional crop varieties, but the available data suggest that roughly 0.05 to 1 percent of these seeds are contaminated with transgenic sequences. This seemingly small percentage must not be underestimated. For example, we calculated the tonnage of transgenically
contaminated corn seeds that would have been planted in fields of traditional corn varieties if the seed supply were contaminated at a one percent rate. Our calculations, based on U.S. Department of Agriculture (USDA) data on corn acres planted with traditional varieties in 2002, suggest a total of 6,250 tons of contaminated seeds—an amount that would fill 240 large tractor-trailer trucks.
Implications of Contamination
Larger studies are needed to determine contamination levels with higher degrees of precision, but even now, the conclusion that Save Our Seeds
The UCS report Gone to Seed recommends a number of actions the federal government, the agriculture industry, and universities should take to preserve the safety of the traditional seed supply. Here are the top priorities:
• The USDA should sponsor a full-scale investigation into the extent, causes, and implications of transgenic contaminants in the traditional seed supply.
• The USDA, the Food and Drug Administration, the Environmental Protection Agency, and appropriate coordinating elements of the federal government should amend the regulations for pharm and industrial crops to ensure that the seed supply for food and feed crops is not contaminated at any level with drugs, vaccines, plastics, or related substances.
• The USDA should establish a reservoir of seeds for non-engineered varieties of major food and feed crops free of transgenically derived sequences. |
the seed supply in the United States is vulnerable to ongoing contamination from a large number of genes has broad implications. In addition to concerns about food safety, the environment, intellectual property, and the agriculture of developing countries, seed contamination has the potential to harm consum-ers and the agricultural economy.
Pharm crops. Pharmaceutical ("pharm") and industrial crops receive special attention in our report because the prod-ucts they are engineered to make—drugs, vaccines, and industrial chemicals—would raise immediate alarms if they contamin-ated the food supply. The realization that seeds for food crops are vulnerable to contamination with pharm and industrial transgenes and that, in fact, some seeds may already have been contaminated is alarming.
Trade. U.S. grain and oilseed exporters face enormous challenges in a global marketplace bristling with regulatory regimes that apply to genetically engineered crops. U.S. companies need to assure export customers that incoming shipments do not contain genetically modified material.
While gene flow and physical commingling during production and transport probably account for most of the unapproved transgenes and transgenic seed varieties present in exported grain and oilseed, traditional crop varieties containing transgenic sequences may also contribute to the problem. Contamination in traditional plant varieties also makes it difficult to supply commodity products free of genetically engineered sequences to those customers who want them.
Organic agriculture. Transgenic contamination of traditional seed varieties poses a special threat to this increasingly important sector of U.S. agriculture. To meet both consumer demand and federal standards that forbid the use of genetically engineered material, organic growers strive to produce crops free of transgenically derived DNA. If, through no fault of their own, organic farmers are unable to supply such products, they potentially face eroding markets. The ease with which the traditional seed supply can be contaminated with transgenically derived DNA frustrates organic farmers and outrages many consumers.
The degree of concern to attach to seed contamination depends on many factors, including the nature of the genes contaminating the seed supply and the levels at which they occur. That information awaits more comprehensive testing, but we must take threats to the seed supply seriously.
It's Not Too Late
Seeds are the wellspring of our food system—the base on which we improve crops and the source to which we return when crops fail. Seeds will be our only recourse if the prevailing belief in the safety of genetic engineering proves misguided. Heedlessly allowing seed contamination to occur amounts to a huge wager on our ability to understand a complicated technology that manipulates life at the most elemental level.
Unless some part of our seed supply is preserved free of genetically engineered sequences, our ability to change course if genetic engineering goes awry will be severely hampered.
UCS hopes that, as a result of this report, the seed and food industries, the scientific community, and the federal government will begin to acknowledge and confront the issues raised by transgenic contaminants in our traditional seed supply. While not entirely reversible, this contamination can be substantially reduced. And, if we act now, we can maintain sources of seeds free of genetically modified material.
Margaret Mellon is director of the Food and Environment Program.
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