title: Field, genetic, and modeling approaches show strong positive selection acting upon an insecticide resistance mutation in Anopheles gambiae s.s.
abstract: Alleles subject to strong, recent positive selection will be swept toward fixation together with contiguous sections of the genome. Whether the genomic signatures of such selection will be readily detectable in outbred wild populations is unclear. In this study, we employ haplotype diversity analysis to examine evidence for selective sweeps around knockdown resistance (kdr) mutations associated with resistance to dichlorodiphenyltrichloroethane and pyrethroid insecticides in the mosquito Anopheles gambiae. Both kdr mutations have significantly lower haplotype diversity than the wild-type (nonresistant) allele, with kdr L1014F showing the most pronounced footprint of selection. We complement these data with a time series of collections showing that the L1014F allele has increased in frequency from 0.05 to 0.54 in 5 years, consistent with a maximum likelihood-fitted selection coefficient of 0.16 and a dominance coefficient of 0.25. Our data show that strong, recent positive selective events, such as those caused by insecticide resistance, can be identified in wild insect populations.
authors.affiliation: Vector Group, Liverpool Tropical School of Medicine, Liverpool, United Kingdom.
authors.forename: Amy
authors.initials: A
authors.lastname: Lynd
authors.forename: David
authors.initials: D
authors.lastname: Weetman
authors.forename: Susana
authors.initials: S
authors.lastname: Barbosa
authors.forename: Alexander
authors.initials: A
authors.lastname: Egyir Yawson
authors.forename: Sara
authors.initials: S
authors.lastname: Mitchell
authors.forename: Joao
authors.initials: J
authors.lastname: Pinto
authors.forename: Ian
authors.initials: I
authors.lastname: Hastings
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Donnelly
mesh_terms: D000483:Alleles; D000818:Animals; D000852:Anopheles / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D056426:Genetic Loci / Q000235:genetics; D005820:Genetic Testing; D005869:Ghana; D006239:Haplotypes / Q000235:genetics; D006720:Homozygote; D007305:Insecticide Resistance / Q000235:genetics*; D015810:Linkage Disequilibrium / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics; D012641:Selection, Genetic