Dynamics of Gene Introgression in the African Malaria Vector Anopheles gambiae

Abstract

Anopheles gambiae is a major malaria vector in Africa and a popular model species for a variety of ecological, evolutionary, and genetic studies on vector control. Genetic manipulation of mosquito vectorial capacity is a promising new weapon for the control of malaria. However, the release of exotic transgenic mosquitoes will bring in novel alleles in addition to the parasite-inhibiting genes, which may have unknown effects on the local population. Therefore, it is necessary to develop methodologies that can be used to evaluate the spread rate of introduced genes in A. gambiae. In this study, the effects and dynamics of genetic introgression between two geographically distinct A. gambiae populations from western Kenya (Mbita) and eastern Tanzania (Ifakara) were investigated with amplified fragment length polymorphisms (AFLPs) and microsatellite markers. Microsatellites and polymorphic cDNA markers revealed a large genetic differentiation between the two populations (average F ST ¼ 0.093, P , 0.001). When the two strains were crossed in random mating between the two populations, significant differences in the rate of genetic introgression were found in the mixed populations. Allele frequencies of 18 AFLP markers (64.3%) for Mbita and of 26 markers (92.9%) for Ifakara varied significantly from F 5 to F 20 . This study provides basic information on how a mosquito release program would alter the genetic makeup of natural populations, which is critical for pilot field testing and ecological risk evaluation of transgenic mosquitoes.

Susceptibility of Anopheles arabiensis Mosquito Pupal Stage to Bioactivities of Varicosporium elodeae and Articulospora inflata

“…They were selected and differentiated using both physical and molecular characterisations. The Anopheles arabiensis pupae were reared in a meshed cage at 25 o C and 70% relative humidity under 14L : 10D photoperiod with slight modifications according to Zhong et al ( 2006). They were fed daily with Tetramin® fish food.…”

Genotyping Tools for Mycobacterium ulcerans Drawbacks and Future Prospects

“…Following these findings, coupled with the high sequence similarity among MU isolates, there has not been much application of these tools in M. ulcerans genetic studies. Although these tools seem less attractive to BU researchers, they have been used in other fields for molecular epidemiological studies [ 54 , 56 , 58 , 59 ]. Similar approaches could be recommended to M. ulcerans research.…”

Evaluation of the potency of some entomopathogenic bacteria isolated from insect cadavers on Anopheles arabiensis Giles (Order: Dipthera; Family: Culicidae) mosquito larvae in Nigeria

“…They were selected and differentiated using both physical and molecular characterisations. The A. arabiensis larvae were reared in a meshed cage at 25°C and 70% relative humidity under 14L:10D photoperiod with slight modifications according to Zhong et al (2006). They were fed daily with Tetramin® fish food.…”