A genetic engineering methodology for insect pest control: female sterilizing genes

Abstract

We propose a novel method to control insect pest populations by integrating into the genome of the target species a gene fusion that serves as a dominant female sterilizing (FS) gene. Based on the developmental regulation, regulatory sequences from vitellogenin and/or chorion protein genes have been identified as suitable for construction of FS gene fusions. These promoters, which respond to tissue- and stage-specific developmental signals, can be linked to a variety of structural gene elements such as those of a scrambled chorion protein, a signal sequence-deleted neutral protease, a phospholipase, an altered tubulin or a toxin. Such a FS gene fusion, because of its tissue and developmental stage specificity, could be expected to be expressed only in adult ovaries with resulting disruption of ovarian functions. In order to introduce the FS gene into the genome of the target species we suggest placing it at a neomycin resistance or other appropriate selectable genetic marker between the termini of a Drosophila transposing P-element and transforming the germline cells in embryo. Males carrying the S gene will transmit it to their progeny which would be all female sterile. Theoretical calculations suggest that target insect populations will be reduced substantially in two to four generations if the ratio of FS males to endemic males is maintained 10:1. It is also theoretically possible to construct a FS gene which would undergo replicative transposition and thus maintain its self in the population in a high copy number thus causing continued decline in the number of pests. The current genetic engineering method allows adapting these principles to control a wide variety of insect pest species.