title: Molecular polymorphism, differentiation and introgression in the period gene between Lutzomyia intermedia and Lutzomyia whitmani.
abstract: BACKGROUND
  Lutzomyia intermedia and Lutzomyia whitmani (Diptera: Psychodidae) are important and very closely related vector species of cutaneous leishmaniasis in Brazil, which are distinguishable by a few morphological differences. There is evidence of mitochondrial introgression between the two species but it is not clear whether gene flow also occurs in nuclear genes.
  
  
  RESULTS
  We analyzed the molecular variation within the clock gene period (per) of these two species in five different localities in Eastern Brazil. AMOVA and Fst estimates showed no evidence for geographical differentiation within species. On the other hand, the values were highly significant for both analyses between species. The two species show no fixed differences and a higher number of shared polymorphisms compared to exclusive mutations. In addition, some haplotypes that are "typical" of one species were found in some individuals of the other species suggesting either the persistence of old polymorphisms or the occurrence of introgression. Two tests of gene flow, one based on linkage disequilibrium and a MCMC analysis based on coalescence, suggest that the two species might be exchanging alleles at the per locus.
  
  
  CONCLUSIONS
  Introgression might be occurring between L. intermedia and L. whitmani in period, a gene controlling behavioral rhythms in Drosophila. This result raises the question of whether similar phenomena are occurring at other loci controlling important aspects of behavior and vectorial capacity.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Instituto Oswaldo Cruz--Fiocruz, Rio de Janeiro, Brazil. camilamazzoni@uol.com.br
authors.forename: Camila J
authors.initials: CJ
authors.lastname: Mazzoni
authors.forename: Nataly A
authors.initials: NA
authors.lastname: Souza
authors.forename: Claudia
authors.initials: C
authors.lastname: Andrade-Coelho
authors.forename: Charalambos P
authors.initials: CP
authors.lastname: Kyriacou
authors.forename: Alexandre A
authors.initials: AA
authors.lastname: Peixoto
mesh_terms: D000818:Animals; D001483:Base Sequence; D001938:Brazil; D029721:Drosophila Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D056950:Period Circadian Proteins; D010802:Phylogeny; D011110:Polymorphism, Genetic; D011576:Psychodidae / Q000235:genetics*; D013045:Species Specificity
chemical_list: D029721:Drosophila Proteins; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins