| Summary: | <p>The development of behavioural resistance in <em>Anopheles</em> mosquitoes is an important threat to the sustainability of current vector interventions, which selectively target mosquitoes that are found indoors. Changes in the following behaviour have been reported in several <em>Anopheles</em> vectors: biting time, host preference, biting and resting behaviour. However, a critical review of the published literature reveals that behavioural resistance has not been demonstrated clearly in <em>Anopheles</em>, highlighting important limitations in using entomological data to investigate the evolution of behaviour.</p> <p>The availability of next generation sequencing and low-cost custom genotyping technologies makes it possible to investigate behavioural resistance using genetic information as an alternative approach. Using such technologies, this thesis aims to investigate whether <em>Anopheles</em> vectors are evolving towards outdoor-biting behaviour ('exophagy') by examining the genetic difference between the indoor- and -outdoor population of the main African malaria vectors, <em>An. coluzzii</em> and <em>An. gambiae</em> from The Gambia and Uganda, respectively. We also investigated the role of olfactory-related genes in driving the potential genetic difference between the two populations.</p> <p>We found limited divergence between the two populations overall, however close inspection identified SNPs potentially associated with outdoor-biting behaviour as well as genomic regions displaying elevated levels of differentiation between the two populations. Most notably, gustatory receptors, <em>Gr11</em> and <em>Gr12</em> and the odour receptor, OR1 were identified as well as, genes related to transcription, signal transduction and catalysis. We discuss the potential role of these genes in determining biting behaviour and suggest that further investigation of these genomic regions is required to confirm the early-stage divergence of indoor- and outdoor-biting Anopheles populations.</p>
|
|---|