Genetically Modified Plants

University of Minnesota, St. Paul

Although there is no one absolute definition of a genetically modified (GM) plant, to some it is any plant that has had its genes deliberately altered by humans, by whatever means. This definition includes all plants produced by conventional plant breeding. Even though specific genes cannot be altered deliberately using conventional plant breeding, these conventional processes modify many genes simultaneously in statistically predictable ways. Hence conventionally produced plants can be considered GM plants, broadly speaking.

To most others, a GM plant is more narrowly defined as a plant that has been produced using transgenic methods. These plants are also called transgenic or genetically engineered plants. Transgenic methods are molecular methods that enable the transfer of a gene or potentially a group of genes from an individual of one species to an individual or individuals of a different species. Currently, there are two common methods by which purified genes are introduced into plant cells: one uses the Ti plasmid of Agrobacterium tumefaciens to transfer the gene as a part of the plasmid; the other uses a metal particle or fiber or an electric pulse to pierce the cell wall and carry the gene into the nucleus (also called gene gun or electroporation). Transgenic methods enable humans to alter specific genes deliberately. The term transgenic is sometimes restricted only to genetic transfers across the species boundary, but usually includes molecular gene transfers within species as well.

The European Union uses GM plants in the narrow sense in discussing the regulation of biotechnology. Within the Cartagena Protocol on Biosafety under the Convention on Biodiversity, the term living modified organism is defined as a GM plant (narrow sense) that is intended to be grown, which excludes grain shipments and most other trade from consideration. The U.S. Office of Science and Technology Policy, which authorized the Coordinated Framework for the regulation of biotechnology in the United States uses GM plants in the narrow sense, except that it is broadened slightly to include a couple of methods that would normally be considered conventional methods. All of these organizations have chosen a definition of GM plants to exclude conventional plant breeding, in part because they do not want to regulate conventional plant breeding.

Although it has become less common, several others have used GM plants (broad sense) to blur the distinction between transgenic plants and conventionally produced plants. Because commercialized conventionally produced plants and their food products have generally been assumed to be safe for the environment and human consumption, blurring the distinction has often been a device to suggest that there are few legitimate concerns about transgenic plants. More recently, this argument has been reversed. Some conventionally produced plants are in fact potentially harmful to the environment or human health, and it may become useful to evaluate the potential dangers associated with some of these plants.

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