title: Divergence with gene flow in Anopheles funestus from the Sudan Savanna of Burkina Faso, West Africa.
abstract: Anopheles funestus is a major vector of malaria across Africa. Understanding its complex and nonequilibrium population genetic structure is an important challenge that must be overcome before vector populations can be successfully perturbed for malaria control. Here we examine the role of chromosomal inversions in structuring genetic variation and facilitating divergence in Burkina Faso, West Africa, where two incipient species (chromosomal forms) of A. funestus, defined principally by rearrangements of chromosome 3R, have been hypothesized. Sampling across an approximately 300-km east-west transect largely contained within the Sudan-Savanna ecoclimatic zone, we analyzed chromosomal inversions, 16 microsatellite loci distributed genomewide, and 834 bp of the mtDNA ND5 gene. Both molecular markers revealed high genetic diversity, nearly all of which was accounted for by within-population differences among individuals, owing to recent population expansion. Across the study area there was no correlation between genetic and geographic distance. Significant genetic differentiation found between chromosomal forms on the basis of microsatellites was not genomewide but could be explained by chromosome 3R alone on the basis of loci inside and near inversions. These data are not compatible with complete reproductive isolation but are consistent with differential introgression and sympatric divergence between the chromosomal forms, facilitated by chromosome 3R inversions.
authors.affiliation: Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Indiana 46556, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Michel
authors.forename: Olga
authors.initials: O
authors.lastname: Grushko
authors.forename: Wamdaogo M
authors.initials: WM
authors.lastname: Guelbeogo
authors.forename: Neil F
authors.initials: NF
authors.lastname: Lobo
authors.forename: N'Fale
authors.initials: N
authors.lastname: Sagnon
authors.forename: Carlo
authors.initials: C
authors.lastname: Costantini
authors.forename: Nora J
authors.initials: NJ
authors.lastname: Besansky
mesh_terms: D000354:Africa, Western; D000818:Animals; D000852:Anopheles / Q000145:classification / Q000235:genetics*; D002050:Burkina Faso; D007446:Chromosome Inversion; D016000:Cluster Analysis; D004272:DNA, Mitochondrial / Q000235:genetics; D051456:Gene Flow; D017344:Genes, Insect; D014644:Genetic Variation; D005843:Geography; D007303:Insect Vectors / Q000235:genetics*; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic
chemical_list: D004272:DNA, Mitochondrial