Analysis of Risks of Transgenic Insects for Pest Management: Past and Future Guidelines

摘要

Genetic modification using recombinant DNA methods can now be used, almost routinely, to transform pest and beneficial insects that could be used to improve pest management programs. Goals include modifying mosquitoes, and other insects that transmit human and animal diseases, so that they are unable to transmit the causal pathogens. Transgenic methods could improve genetic control programs by producing sterile males or producing only females. Other goals include producing honey bees and silk moths that are disease resistant or have other desirable traits. Natural enemies used in biological control programs could be modified to enhance their effectiveness in several ways. Risk assessments must be conducted prior to releasing transgenic insects into the environment for either short term experiments or permanent establishment. Potential risk issues to be resolved prior to releases include whether: the inserted gene(s) (trait) is stable; the traits (especially pesticide or antibiotic resistance genes) can be horizontally transferred to other populations or species; released insects will perform as expected with regard to their geographic distribution, host or prey specificity and other biological attributes; released insects will have unintended environmental effects; and, in the case of short term releases, the released insects can be recovered from field sites. Risk assessments of fitness and host specificity are relatively easy to assess in the laboratory, but horizontal gene transfer and unintended effects on ecosystem function are more challenging. Permission to release a transgenic insect will have to be obtained from (several ?) regulatory agencies. Initial releases initially are being made into small plots, perhaps in cages and, in the USA, are intended to be short term experiments. Current regulations of the U.S. Department of Agriculture require the researcher to retrieve all transgenic insects from the environment at the end of the experiment. If transgenic insect strain(s) perform well and risk assessments are completed satisfactorily, permanent releases into the environment may be allowed, but guidelines for such releases are lacking. Many pest management programs, especially those involving replacement of pest populations by a transgenic population, will require permanent establishment in the environment. Several drive mechanisms have been proposed to insert genes into populations but analyses of the potential risks of such drive mechanisms have not been carried out. International guidelines are needed for risk analyses of transgenic insects because insects are highly mobile and could move beyond individual countries' boundaries.