Technology for transforming the germ line in economically important insects

The development of a germ line transformation methodology for insects of agricultural and medical importance is critical to the implementation of novel and highly efficient means of insect management using molecular biological techniques. Currently, an efficient means of gene transfer, using the P transposable element based vector system, is possible in only one insect, Drosophila melanogaster, and this methodology has not been applicable to other insects. Progress has been made in modifying the P element so that it might function in non-drosophilids, although a system fully useful for a wide range of insects is still prospective. Other transposable element systems from Drosophila having the potential for gene vector development have been identified, specifically the hobo and mariner transposons. For both these elements, homologous genes or DNA sequences have been found in distantly related insects, suggesting that their mobility properties might be maintained in these and other insects, or that they may be used as probes to isolate related transposons. Continued studies along these lines hold the greatest promise, at present, for gene vector development. An immediate use of gene transformation in economically important insects may be for genetic sexing and male sterilization in the sterile insect technique. This is due to the understanding of sex specific gene expression and sex determination activity in D. melanogaster, as well as the genetic material available from this and other organisms. Model systems for highly efficient genetic sexing and sterilization based on recombinant DNA manipulation and gene transformation are discussed. (author). 41 refs