title: Three sympatric clusters of the malaria vector Anopheles culicifacies E (Diptera: Culicidae) detected in Sri Lanka.
abstract: BACKGROUND
  The disease re-emergence threat from the major malaria vector in Sri Lanka, Anopheles culicifacies, is currently increasing. To predict malaria vector dynamics, knowledge of population genetics and gene flow is required, but this information is unavailable for Sri Lanka. This study was carried out to determine the population structure of An. culicifacies E in Sri Lanka.
  
  
  METHODS
  Eight microsatellite markers were used to examine An. culicifacies E collected from six sites in Sri Lanka during 2010-2012. Standard population genetic tests and analyses, genetic differentiation, Hardy-Weinberg equilibrium, linkage disequilibrium, Bayesian cluster analysis, AMOVA, SAMOVA and isolation-by-distance were conducted using five polymorphic loci.
  
  
  RESULTS
  Five microsatellite loci were highly polymorphic with high allelic richness. Hardy-Weinberg Equilibrium (HWE) was significantly rejected for four loci with positive F(IS) values in the pooled population (p < 0.0100). Three loci showed high deviations in all sites except Kataragama, which was in agreement with HWE for all loci except one locus (p < 0.0016). Observed heterozygosity was less than the expected values for all sites except Kataragama, where reported negative F(IS) values indicated a heterozygosity excess. Genetic differentiation was observed for all sampling site pairs and was not supported by the isolation by distance model. Bayesian clustering analysis identified the presence of three sympatric clusters (gene pools) in the studied population. Significant genetic differentiation was detected in cluster pairs with low gene flow and isolation by distance was not detected between clusters. Furthermore, the results suggested the presence of a barrier to gene flow that divided the populations into two parts with the central hill region of Sri Lanka as the dividing line.
  
  
  CONCLUSIONS
  Three sympatric clusters were detected among An. culicifacies E specimens isolated in Sri Lanka. There was no effect of geographic distance on genetic differentiation and the central mountain ranges in Sri Lanka appeared to be a barrier to gene flow.
authors.affiliation: Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Jayewardenepura, 10250, Sri Lanka. ireshanh@gmail.com.
authors.forename: Iresha Nilmini
authors.initials: IN
authors.lastname: Harischandra
authors.affiliation: Department of Chemistry, Faculty of Science, University of Colombo, Cumarathunga Munidasa Mawatha, Colombo 04, 00300, Sri Lanka. rsdassanayake@gmail.com.
authors.forename: Ranil Samantha
authors.initials: RS
authors.lastname: Dassanayake
authors.affiliation: Department of Zoology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Jayewardenepura, 10250, Sri Lanka. nissankakolitha@gmail.com.
authors.forename: Bambaranda Gammacharige Don Nissanka Kolitha
authors.initials: BG
authors.lastname: De Silva
mesh_terms: D000818:Animals; D000852:Anopheles / Q000235:genetics*; D001499:Bayes Theorem; D005260:Female; D005788:Gene Pool; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D006801:Humans; D007303:Insect Vectors / Q000235:genetics*; D008288:Malaria / Q000635:transmission*; D018895:Microsatellite Repeats / Q000235:genetics*; D013188:Sri Lanka / Q000453:epidemiology