title: Genetic polymorphism at an odorant receptor gene (Or39) among mosquitoes of the Anopheles gambiae complex in Senegal (West Africa).
abstract: BACKGROUND
  Olfaction plays a significant role in insect behavior during critical steps of their life-cycle, such as host-seeking during foraging or the search for a mate. Here, we explored genetic polymorphism within and divergence between sibling species of the African malaria mosquito, Anopheles gambiae sensu lato in the gene sequence and encoded peptides of an odorant receptor, Or39. This study included sympatric specimens of An. gambiae sensu stricto, An. coluzzii and An. arabiensis sampled together in the village of Dielmo, Senegal.
  
  
  RESULTS
  A 1,601 bp genomic sequence composed of 6 exons and 5 introns was obtained for Or39 from 6-8 mosquitoes in each of the 3 species. DNA sequence analysis revealed a high level of molecular polymorphism (π = 0.0154; Haplotype diversity = 0.867) and high overall genetic differentiation between taxa (Fst > 0.92, P < 0.01). In total, 50 parsimony informative sites were recorded. Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein. Each of the 6 different identified peptides was species-specific and none was shared across species. Most aminoacid changes were located on the intracellular domains of the protein. However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain.
  
  
  CONCLUSIONS
  Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces.
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR IRD 224-CNRS 5290-UM1-UM2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, Montpellier, cedex 5 34394, France. au.arnal@gmail.com.
authors.forename: Audrey
authors.initials: A
authors.lastname: Arnal
authors.forename: Pierre
authors.initials: P
authors.lastname: Kengne
authors.forename: Cecile
authors.initials: C
authors.lastname: Brengues
authors.forename: Kounbobr Roch
authors.initials: KR
authors.lastname: Dabire
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Diabate
authors.forename: Hubert
authors.initials: H
authors.lastname: Bassene
authors.forename: Frederic
authors.initials: F
authors.lastname: Simard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D005091:Exons; D007438:Introns; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D018035:Receptors, Odorant / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D017931:DNA Primers; D018035:Receptors, Odorant