Quantitative Trait Loci That Control Vector Competence for Dengue-2 Virus in the Mosquito Aedes aegypti

Abstract

Abstract Quantitative trait loci (QTL) affecting the ability of the mosquito Aedes aegypti to become infected with dengue-2 virus were mapped in an F1 intercross. Dengue-susceptible A. aegypti aegypti were crossed with dengue refractory A. aegypti formosus. F2 offspring were analyzed for midgut infection and escape barriers. In P1 and F1 parents and in 207 F2 individuals, regions of 14 cDNA loci were analyzed with single-strand conformation polymorphism analysis to identify and orient linkage groups with respect to chromosomes I–III. Genotypes were also scored at 57 RAPD-SSCP loci, 5 (TAG)n microsatellite loci, and 6 sequence-tagged RAPD loci. Dengue infection phenotypes were scored in 86 F2 females. Two QTL for a midgut infection barrier were detected with standard and composite interval mapping on chromosomes II and III that accounted for ∼30% of the phenotypic variance (σp2) in dengue infection and these accounted for 44 and 56%, respectively, of the overall genetic variance (σg2). QTL of minor effect were detected on chromosomes I and III, but these were not detected with composite interval mapping. Evidence for a QTL for midgut escape barrier was detected with standard interval mapping but not with composite interval mapping on chromosome III.