Genetic relationships among Aedes aegypti collections in Venezuela as determined by mitochondrial DNA variation and nuclear single nucleotide polymorphisms.

A population genetic analysis of gene flow was conducted among 619 Aedes aegypti from nine collections distributed among six geographic regions of Venezuela. Genetic markers included a 387-basepair region of the mitochondrial NADH dehydrogenase 4 (ND4) gene and single nucleotide polymorphisms (SNPs) at 11 nuclear loci. Genotypes at SNP loci were identified using melting curve analysis. Six different ND4 haplotypes were detected and patterns of variation suggested that collections were isolated by distance. The variance in SNP allele frequencies was much less than the variance in haplotype frequencies and a pattern of isolation by distance was not detected. Aedes aegypti from eight collections were orally challenged with dengue 2 virus. Disseminated infection rates ranged from 77% to 95%. The percentage of mosquitoes exhibiting a midgut infection barrier ranged from 2% to 15%, and those exhibiting a midgut escape barrier ranged from 2% to 18%. Venezuelan Ae. aegypti appear to be susceptible to dengue virus infection.