L' α-Glycérophosphate-déshydrogénase du moustique Culex pipiens: Génétique formelle, linkage et étude de populations

Multiple alleles and low variability of glycerol-3-phosphate dehydrogenase in Aedes albopictus (Diptera: Culicidae) from Peninsular Malaysia

1. A total of 8 samples from three natural populations and a laboratory strain of Aedes albopictus were analysed for glycerol-3-phosphate dehydrogenase phenotypes by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by three codominant Gpd alleles. 3. There was low variability, with the heterozygosity in the variable samples ranging from 0.02 to 0.12. 4. The commonest allele in all the population samples was GpdB which encoded an electrophoretic band with intermediate mobility. 5. There was no temporal or spatial variation.

Genetic and biochemical studies of the highly active esterases A' and B associated with organophosphate resistance in mosquitoes of the Culex pipiens complex

The highly active esterases A' and B that cannot be dissociated from OP resistance in Culex pipiens from France and California are shown to have equivalent Km values (2.1 x 10(-6) M/min/mosquito) but different turnover rates (Vm = 2.13 and 0.57 x 10(-6) M/min/mosquito, respectively) and pH for maximum activity. Both enzymes have broad substrate specificities and at least one, esterase A', can hydrolyze OP insecticides. In addition, esterases A' and B are coded by two closely linked genes, Est-3 and Est-2, respectively (0.67 unit of crossing over), located on the same autosome as pl, a locus attributed to linkage group III. The estimated distance between Est-2 and pl was 9.4 units.

Allozyme polymorphism in the parasitic hymenoptera Diadromus pulchellus WSM. (Ichneumonidae)

The allozyme polymorphism ofDiadromus pulchellushas been analysed at 22 loci, the expression of one (Est-4) being male-limited. Six loci were found polymorphic for two (Ldh-1,Ldh-2,Acp-2,PgiandSdh) or three (Est-3) codominant alleles. Allele frequencies are similar in males and females at four loci in a laboratory population but there are important heterozygote deficiencies in females at three of them. The possibilities of negative heterosis or assortative mating to explain this deficiency are discussed.

Esterases in the mosquito Culex pipiens pipiens L: formal genetics and polymorphism of adult esterases

The genetics of two esterase loci active in autogenous adults of the mosquito Culex pipiens pipiens L. has been studied by means of starch gel electrophoresis. Three alleles at the Est-1 locus and eight at the Est-2 locus are described. Both loci have a null allele. Active alleles are codominant and there is no hybrid enzyme in heterozygotes. The Est-1 locus codes esterases preferentially hydrolyzing alpha-naphthylacetate and the Est-2 locus esterases preferentially hydrolyzing beta-naphthylacetate. Strains homozygous for both loci were selected. Linkage studies of the two loci have shown that they are not sex linked but are linked to each other, the crossover frequency being 8.6%. The polymorphism of two laboratory and two natural populations is described for both loci. Phenotypic distributions are in good agreement with Hardy-Weinberg expectations.