How Analogous are Exotic Introductions to Genetically Engineered Plants?
Saturday, April 13, 2002 - 1:30pm - 2:20pm
James Hancock (Michigan State University)
Genetically engineered crops are not analogous to exotic introductions. Exotic species commonly become invasive when they are introduced into a new area where there are few to none of the natural constraints with which they evolved, and so they fill a new niche and their numbers explode. Most of the successful exotics are already good colonizers somewhere else and carry a whole syndrome of traits associated with weediness. Hybridization with local relatives may facilitate this process. Transgenic crops present a very different situation. The crop antecedents are generally poor competitors outside the agroecosystem and carry few weediness traits. After the crop is engineered, it will not be removed from the complex array of natural constraints that currently faces it, and in most cases only one of those constraints will be removed by the addition of a new trait. In fact, it is much easier to predict the environmental risk of transgenic crops than an exotic introduction, as the level of risk in transgenics can be measured by evaluating the fitness impact of a single engineered trait, rather than a whole syndrome of potentially invasive traits. The risk of most transgene deployments can be effectively predicted by considering the phenotype of the transgene and the overall invasiveness of the crop itself.