Gene flow between domestic and sylvan populations of Aedes aegypti (Diptera: Culicidae) in North Cameroon.

Polymorphisms at eight microsatellite loci and a fragment of the mitochondrial DNA (mtDNA)-ND4 gene were surveyed in Aedes aegypti (L.) (Diptera: Culicidae) populations collected from six localities in North Cameroon, with emphasis on comparing domestic versus sylvan populations. The microsatellites revealed significant genetic differentiation among sylvan populations, with mean F(ST) = 0.066. Domestic collections were genetically homogeneous (mean F(ST) = 0.012). No pattern of isolation by distance was detected, and one of highest levels of genetic differentiation was estimated between populations sampled a few kilometers apart, each in a distinctly different ecological environment (F(ST) = 0.076). Analyses of mtDNA-ND4 polymorphisms and divergence between the two neighboring populations revealed increased genetic diversity within the domestic population, with molecular signatures suggesting recent demographic expansion, whereas a single haplotype was observed in the sylvan sample. These data suggest reduced gene flow between sylvan and domestic Ae. aegypti populations in North Cameroon, reminiscent of the situation for Ae. aegypti in Kenya in East Africa.