Genetic structure of Anopheles gambiae populations on islands in northwestern Lake Victoria, Uganda

• Published in: Malaria Journal
• Main Authors: Coulibaly Mamadou B, Michel Andrew P, Stump Aram, Mukwaya Louis G, Kayondo Jonathan K, Besansky Nora J, Collins Frank H
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2005
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Four Islands
• Online Access: https://doi.org/10.1186/1475-2875-4-59; https://doaj.org/article/d381a7a4aa5d4c93a4023606e50cff6e

Abstract Background Alternative means of malaria control are urgently needed. Evaluating the effectiveness of measures that involve genetic manipulation of vector populations will be facilitated by identifying small, genetically isolated vector populations. The study was designed to use variation in microsatellite markers to look at genetic structure across four Lake Victoria islands and two surrounding mainland populations and for evidence of any restriction to free gene flow. Methods Four Islands (from 20–50 km apart) and two surrounding mainland populations (96 km apart) were studied. Samples of indoor resting adult mosquitoes, collected over two consecutive years, were genotyped at microsatellite loci distributed broadly throughout the genome and analysed for genetic structure, effective migration (Nem) and effective population size (Ne). Results Ne estimates showed island populations to consist of smaller demes compared to the mainland ones. Most populations were significantly differentiated geographically, and from one year to the other. Average geographic pair-wise F ST ranged from 0.014–0.105 and several pairs of populations had Ne m < 3. The loci showed broad heterogeneity at capturing or estimating population differences. Conclusion These island populations are significantly genetically differentiated. Differences reoccurred over the study period, between the two mainland populations and between each other. This appears to be the product of their separation by water, dynamics of small populations and local adaptation. With further characterisation these islands could become possible sites for applying measures evaluating effectiveness of control by genetic manipulation.