Gene flow among populations of Anopheles gambiae: a critical review

The success of genetic-control programmes aimed at introducing genes into wild Anopheles gambiae populations depends on our understanding of the genetic structure of these populations. Population-genetic studies are required for identifying discrete population groups across Africa, determining their geographical distribution and evaluating the degree to which they may be reproductively isolated. Population studies are also needed to estimate the rate at which genes may spread within and between populations at various spatial scales and to identify biological and physical features of the environment that may interfere with their movement. Studies of the mechanisms of reproductive isolation between molecular/chromosomal forms of An. gambiae can be used to validate the results of population-genetic approaches and aid in the development of reproductively competitive laboratory strains. In the following, we review past and recent studies that cover these aspects of An. gambiae population genetics and ecology. We critically discuss the validity of the designs and methodologies involved in an attempt to provide a sound basis for future undertakings. We also discuss new directions and priorities in the light of the recent developments toward a genetic-control strategy for An. gambiae.