Spatial genetic structure ofAedes aegyptimosquitoes in mainland Southeast Asia

Abstract

Aedes aegypti mosquitoes originated in Africa and are thought to have spread recently to Southeast Asia, where they are the major vector of dengue. Thirteen microsatellite loci were used to determine the genetic population structure of A. aegypti at a hierarchy of spatial scales encompassing 36 sites in Myanmar, Cambodia and Thailand, and two sites in Sri Lanka and Nigeria. Low, but significant, genetic structuring was found at all spatial scales (from 5 to >2000 km) and significant FIS values indicated genetic structuring even within 500 m. Spatially dependent genetic-clustering methods revealed that although spatial distance plays a role in shaping larger-scale population structure, it is not the only factor. Genetic heterogeneity in major port cities and genetic similarity of distant locations connected by major roads, suggest that human transportation routes have resulted in passive long-distance migration of A. aegypti. The restricted dispersal on a small spatial scale will make localized control efforts and sterile insect technology effective for dengue control. Conversely, preventing the establishment of insecticide resistance genes or spreading refractory genes in a genetic modification strategy would be challenging. These effects on vector control will depend on the relative strength of the opposing effects of passive dispersal.

Population Genetic Structure of Aedes (Stegomyia) aegypti (L.) at a Micro-Spatial Scale in Thailand: Implications for a Dengue Suppression Strategy

“…Our results confirm the finding of Hlaing et al [5] which reported low but significant genetic structure at all spatial scales within mainland Southeast Asia. Seasonal shifts in allele frequency in the villages may occur when there is a particularly productive water container which leads to a local explosion in mosquito numbers and a genetic bottleneck has changed allele frequencies within this container.…”

“…aegypti by humans [5], [31]. Movement in the Subdistrict is intensive between some villages in the complex.…”

“…A Mantel test of the linearized F ST transformation [ F ST /(1− F ST )] with the natural log of geographical distance [16] was made with POPTOOLS version 2.6 [5] to investigate whether gene flow was largely restricted by geographic distance (isolation by distance). Significance of Mantel tests was determined by permutation (10,000 randomizations).…”

“…Another study using 13 microsatellite loci to look at population genetics of Ae. aegypti in mainland Southeast Asian countries revealed genetic structure at all spatial scales including those at a distance of less than 500 m [5]. The short-range nature of dispersal of Ae .…”

Wolbachia infection increases recapture rate of field-released Drosophila melanogaster

“…If Wolbachia does reduce the tendency to participate in long-distance dispersal then it could potentially play a role in population substructure (Hlaing et al 2010) and hence processes like speciation (Craft et al 2010;Drummond et al 2010;Lehrian et al 2010). In an applied context, the capacity to limit dispersal by the artificial introduction of Wolbachia into insect species would be attractive in the case of agricultural pests where dispersal is a critical determinant of invasion success (Liebhold and Tobin 2008).…”