Genetic transformation is an important technology that provides unique opportunities to find, isolate, and analyze genes, as well as to create organisms with unique functional characteristics. Insect biologists have been developing genetic transformation technologies that rely extensively on transposable elements. A number of class II transposable elements isolated originally from insects have been converted into broad host range insect gene vectors. Class II transposable elements are particularly amenable to gene vector development, although they suffer from some limitations such as low rates of recombination. Use of these gene vectors requires the physical introduction of the vectors into developing insect embryos by microinjection. Microinjection methods vary to accommodate the unique physical and developmental characteristics of the target insects. All methods rely on the use of fine glass needles in conjunction with micromanipulators and a microscope. A serious constraint on the use of existing systems can be the inefficiency of successfully delivering the gene vectors to the germ cells of the developing embryo. The general method for vector delivery to insect germ cells is described, as well as variations that are useful under some conditions. Leopold, R. A., Hughes, K. J., and DeVault, J. D. (1996) Using electroporation and a slot cuvette to deliver plasmid DNA to insect embryos. Miller, L. H., Sakai, R. K., Romans, P., Gwadz, R. W., Kantoff, P., and Coon, H. G. (1987) Stable integration and expression of a bacterial gene in the mosquito Loukeris, T. G., Arca, B., Livadaras, I., Dialektaki, G., and Savakis, C. (1995) Introduction of the transposable element Fraser, M. J. The TTAA-specific family of transposable element: identification, functional characterization, and utility for transformation of insects. In Sundararajan, P., Atkinson, P. W., and O’Brochta, D. A. (1999) Transposable element interactions in insects: Crossmobilization of Catteruccia, F., Nolan, T., Loukeris, T. G., Blass, C., Savakis, C., Kafatos, F. C., et al. (2000) Stable germline transformation of the malaria mosquito Peloquin, J. J., Thibault, S. T., Schouest, L. P., and Miller, T. A. (1997) Electromechanical microinjection of pink bollworm Jasinskiene, N., Coates, C. J., Benedict, M. Q., Cornel, A. J., Rafferty, C., Salazar-Rafferty, C., et al. (1998) Stable, transposon mediated transformation of the yellow fever mosquito, Coates, C. J., Jasinskiene, N., Pott, G. B., and James, A. A. (1999) Promoter-directed expression of recombinant fire-fly luciferase in the salivary glands of Pinkerton, A. C., Michel, K., O’Brochta, D. A., and Atkinson, P. W. (2000) Green fluorescent protein as a genetic marker in transgenic Moreira, L. A., Edwards, M. J., Adhami, F., Jasinskiene, N., James, A. A., and Jacobs-Lorena, M. (2000) Robust gut-specific gene expression in transgenic Kokoza, V., Ahmed, A., Cho, W. L., Jasinskiene, N., James, A. A., and Raikhel, A. (2000) Engineering blood meal-activated systemic immunity in the yellow fever mosquito, transposon mediates germ-line transformation of the Oriental fruit fly and closely related elements exist in its genome. Peloquin, J. J., Thibault, S. T., Staten, R., and Miller, T. A. (2000) Germ-line transformation of pink bollworm (Lepidoptera: Gelechiidae) mediated by the Tamura, T., Thibert, C., Royer, C., Kanda, T., Abraham, E., Kamba, M., et al. (2000) Germline transformation of the silkworm Christophiles, G. K., Livadaras, I., Savakis, C., and Komitopoulou, K. (2000) Two medfly promoters that have originated by recent gene duplication drive distinct sex, tissue and temporal expression patterns. Source.