The use of microsatellites to study gene flow in natural populations of Anopheles malaria vectors in Africa: potential and pitfalls.

The potential of microsatellites as population genetic markers in the malarial vectors Anopheles gambiae and Anopheles arabiensis was assessed using 4 loci. Substantial genetic divergence was found not only between these species but also between the Mopti and Forest chromosomal forms of An. gambiae, demonstrating that microsatellites do have the power to detect barriers to gene flow in these mosquitoes. However, application and interpretation of microsatellites was not necessarily straightforward. Despite the use of semiautomated fluorescent technology that enabled fragment sizes to be determined precisely, some difficulty was encountered in allele classification. Sequence analysis revealed insertions/deletions and base changes in the flanking regions of the microsatellite as the probable cause of this problem. The implications of this and other potential pitfalls in the use of microsatellites to study vector populations are discussed.