Est-2 and Est-3 polymorphisms in Culex pipiens L. from Southern France in relation to organophosphate resistance

Est-2 and Est-3 linkage disequilibrium was investigated in 43 natural populations. An association between Est-2(0.64) and Est-3A alleles (or its reverse, Est-3Null and alleles other than Est-2(0.64) was not observed in 19 (1.2%) of the 1599 mosquitoes analyzed, whereas it should have been found in nearly 400 (25%) individuals if the two loci were in equilibrium. This observation is discussed in relation to organophosphate resistance and genetic distance of the two genes.