Location of a gene conferring DDT resistance but no pyrethroid cross-resistance in larvae of Anopheles stephensi.

In larvae of Anopheles stephensi, DDT resistance of 30 to 40-fold, involving no cross-resistance to pyrethroids, showed fully dominant monofactorial inheritance. The gene, termed DDT, is located 36.6 cross-over units from the morphological mutant, black larvae (Bl), on chromosome III. A polygenic system, which confers a 17-fold reduction in susceptibility to knockdown by the pyrethroid, permethrin, also makes a minor contribution to DDT resistance. It was not possible to block DDT resistance with the dehydrochlorinase inhibitor DMC.