Transgenic mosquitoes: the state of the art

Abstract

After almost two decades of effort, the technology for creating transgenic mosquitoes has been developed. Although it requires specialized equipment, skills and facilities, any determined investigator can successfully use the technology. Delivery of transgenes to the germ cells of the host mosquito is accomplished by direct injection of pre-blastoderm embryos using fine, sharp glass needles. This delivery system is inefficient and demands special equipment and a high level of skill. Integration of the transgene into the chromosomes of the host insect is facilitated by the use of transposable-element-based gene vectors. Hermes, mariner, Minos and piggyBac are insect-derived transposable elements that have broad host ranges and function in mosquitoes. The efficiency of integration is between 1% and 10%; meaning 1-10% of the mosquitoes surviving the injection process and producing progeny will produce at least one transgenic offspring. Detecting transgenic mosquitoes is now very efficient with the advent of a wide variety of autofluorescent proteins that can serve as dominant visible genetic markers. The key question in the efforts to develop transgenic strategies for the modification of natural mosquito populations is not whether transgenic mosquitoes refractory to virus or parasite development can be created. Instead, the key questions now are: Can transgenic genotypes be successfully introduced into natural mosquito populations? Will the frequency of introduced transgenes in natural populations increase? Will the genetically modified populations of mosquitoes create the public-health benefit desired?