Simulation of instability in genetic sexing strains: effects of male recombination in association with other biological parameters

Abstract

AbstractGenetic systems have been developed in several insect species for separating males and females prior to releasing sterilized males in pest control programmes using the sterile insect technique. The systems generally depend on translocating a readily selectable gene onto the Y chromosome. A potential source of instability in such a system is genetic recombination in the male. Although such recombination was originally thought to be absent in most cyclorrhaphous Diptera, low levels have recently been found. We have developed a computer model which simulates the progression of instability in the presence of male recombination, which can be used to assess the influence of rate of recombination in combination with a range of associated genetic and biological parameters. Male recombination alone or fitness of the Y-linked translocation were found to contribute relatively little to the rate of progression of instability. By contrast reduced fitness or mating competitiveness associated with the selectable gene had a strong effect. The sex ratio and the ratio of carriers to non-carriers of the selectable gene showed patterns characteristic of the parameters modelled. The relevance of such data to the development of suitable strains for genetic sex-separation and the replacement of strains under mass rearing conditions are discussed.