title: Sex-linked differentiation between incipient species of Anopheles gambiae.
abstract: Emerging species within the primary malaria vector Anopheles gambiae show different ecological preferences and significant prezygotic reproductive isolation. They are defined by fixed sequence differences in X-linked rDNA, but most previous studies have failed to detect large and significant differentiation between these taxa elsewhere in the genome, except at two other loci on the X chromosome near the rDNA locus. Hypothesizing that this pericentromeric region of the X chromosome may be accumulating differences faster than other regions of the genome, we explored the pattern and extent of differentiation between A. gambiae incipient species and a sibling species, A. arabiensis, from Burkina Faso, West Africa, at 17 microsatellite loci spanning the X chromosome. Interspecific differentiation was large and significant across the entire X chromosome. Among A. gambiae incipient species, we found some of the highest levels of differentiation recorded in a large region including eight independent loci near the centromere of the X chromosome. Outside of this region, no significant differentiation was detected. This pattern suggests that selection is playing a role in the emergence of A. gambiae incipient species. This process, associated with efficient exploitation of anthropogenic modifications to the environment, has public health implications as it fosters the spread of malaria transmission both spatially and temporally.
authors.affiliation: Center for Tropical Disease Research and Training, Department of Biological Sciences, University of Notre Dame, Indiana 46556, USA. besansky.1@nd.edu
authors.forename: Aram D
authors.initials: AD
authors.lastname: Stump
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Shoener
authors.forename: Carlo
authors.initials: C
authors.lastname: Costantini
authors.forename: N'Fale
authors.initials: N
authors.lastname: Sagnon
authors.forename: Nora J
authors.initials: NJ
authors.lastname: Besansky
mesh_terms: D000818:Animals; D000852:Anopheles / Q000145:classification / Q000235:genetics*; D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000235:genetics; D005260:Female; D005819:Genetic Markers; D015810:Linkage Disequilibrium; D008297:Male; D010802:Phylogeny; D012733:Sex Differentiation / Q000235:genetics*; D013045:Species Specificity; D014960:X Chromosome
chemical_list: D004275:DNA, Ribosomal; D005819:Genetic Markers; D004247:DNA