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information presented by SeedQuest and The Seed Biotechnology Center at UC Davis

Regulation of genetically engineered varieties

The introduction of genetically engineered (GE) varieties (those developed using recombinant DNA techniques in addition to sexual crossing and selection) has created additional issues for seed genetic purity, particularly for producers seeking to meet organic marketing standards or who are engaged in international trade. The U.S. National Organic Program (NOP) does not allow the use of seed developed using recombinant DNA techniques to produce crops that will be certified as organic. It also requires the use of seeds that have been produced using organic methods when such seeds are commercially available. Current regulations do not specify an acceptable threshold level for the unintended presence of GE materials in an organic product (there is an implied zero tolerance), and there is also no requirement to test for such inadvertent presence. Neither an organic grower nor the organic product would automatically lose organic certification if such unintended contamination occurred.

Nonetheless, it is clearly the expectation of consumers purchasing organic foods that those foods do not contain materials developed using genetic engineering. In addition, GE varieties are individually regulated by national agencies, so approval generally is required from the importing country before those varieties can be legally traded. The presence of even a small amount of an unapproved GE variety, if detected, can block an entire shipment. Thus, achieving and maintaining high seed genetic purity has become even more important following the introduction of GE varieties. The principles for producing seed crops that are free of GE materials are the same as those for seed certification. The main sources of contamination of a seed crop are the prior crop grown in a field, transfer of pollen from a nearby field, and mixtures during harvesting and handling.

Bradford, K. J. 2006. Methods to Maintain Genetic Purity of Seed Stock.  Agricultural Biotechnology in California Series. Publication 8189.
http://anrcatalog.ucdavis.edu/pdf/8189.pdf

In the United States, three agencies have regulatory jurisdiction over genetically engineered organisms: the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA). Equivalent agencies regulate transgenic crops in other countries in the context of agriculture, the environment and food safety and labeling. In the US, once a transgenic variety has been evaluated by the USDA, the FDA and/or the EPA and approved for production and sale (i.e., is de-regulated), there are no additional identity preservation requirements beyond those normally in place for that commodity. So a soybean, cotton or corn variety may contain herbicide or insect resistance, but regulatory agencies have determined that those varieties are substantially equivalent with respect to their food or fiber value to similar varieties without the transgenic traits. This lack of distinction is not the case in many other countries to which U.S. agricultural products are exported. Even in the United States, some processors and retailers are reluctant to include biotech crops in their products due to the possibility of consumer rejection.

On an international scale, the Cartagena Protocol for Biodiversity (CPB) aims to regulate the movement of genetically modified organisms across international borders. The CPB has been signed and ratified by at least 140 countries. It aims to set minimum standards to regulate genetically modified organisms for countries that have signed and ratified it. The importation of biotech seeds or products into countries that have not signed and ratified the CPB, such as the U.S., is not bound by the CPB rules. The implementation of the CPB is still being discussed in international meetings.

There are several methods used to test for the absence or presence of transgenes in seed and grain products, each with its specific advantages and disadvantages. Seed bioassays* for herbicide tolerance are easy to use and relatively inexpensive but require significant time and resources. Lateral flow strips and enzyme-linked immunosorbent assays (ELISAs) use immunological techniques based on antibodies to detect specific proteins associated with the trait of interest. Flow strips are simple and rapid, but can have a relatively short shelf life and their reliability can be significantly influenced by the level of protein in the sample. Various techniques can be used to detect specific DNA sequences, but most commonly the DNA of interest is amplified using polymerase chain reaction (PCR), a procedure that uses enzymes to synthesize specific DNA sequences in the test tube. PCR assays are extremely sensitive, capable of detecting just a few molecules of the target DNA. However, this sensitivity also makes PCR assays subject to false positive results if stringent sample preparation and cleanliness procedures are not followed.

Currently, even though some countries require testing and labeling of transgenic commodities, there are no accepted national or international test standards for detection of specific crop genetic traits. The USDA’s Grain Inspection, Packers and Stockyard Administration is in the process of establishing a U.S. laboratory accreditation system for this purpose, but trait reporting methods can vary among laboratories.