Periodic triggering of an inducible gene for control of a wild population

A possible method of control for the management of wild populations consist s of continual introgression of an inducible transgene by releasing transge nic individuals, with periodic exposure of the population to a trigger. Exp osure to the trigger causes death or sterility in carriers of the transgene , but is otherwise benign. We investigate the effectiveness of various stra tegies for control. We show that suppression of the population density belo w any prespecified level is possible using this technique. At the same time we show that too frequent or too efficient exposure to the trigger can sel ect for non-transgenic genotypes at an intensity such that the population d ensity will be largely unaffected by the trigger, Choices for management pa rameters can ensure that the latter scenario is avoided. We show that relea sing individuals carrying the transgene at more than one locus facilitates density control. (C) 2000 Academic Press.