title: Molecular comparisons of the Culex pipiens (L.) complex esterase gene amplicons.
abstract: The amplification of carboxylesterase genes is a mechanism of organophosphate resistance in Culex mosquitoes. Amplified carboxylesterase genes from an insecticide resistant Culex pipiens strain collected in Cyprus were analysed and compared to other Culex amplified carboxylesterase alleles. A 12 kb section of genomic DNA containing two gene loci coding for carboxylesterase alleles A5 and B5 was cloned and sequenced. A comparison between this amplicon and one from a strain with co-amplified carboxylesterase alleles A2 and B2 revealed a number of differences. The intergenic spacer was 3.7 kb in length in the A5-B5 amplicon (2.7 kb in A2-B2) and contained putative Juan and transposable elements upstream of B5. A fragment of a gene with high homology to aldehyde oxidase was also present immediately downstream of A5. The comparison revealed no differences that would explain the successful spread of the A2-B2 amplicon worldwide whilst the A5-B5 amplicon is restricted to the Mediterranean.
authors.affiliation: Division of Zoology, School of Animal and Microbial Sciences, University of Reading, Whiteknights, Reading RG6 6AJ, UK.
authors.forename: D S
authors.initials: DS
authors.lastname: Buss
authors.forename: A
authors.initials: A
authors.lastname: Callaghan
mesh_terms: D042931:Aldehyde Oxidase / Q000235:genetics; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003465:Culex / Q000201:enzymology* / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D004950:Esterases / Q000235:genetics*; D005784:Gene Amplification / Q000235:genetics*; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D004251:DNA Transposable Elements; D021901:DNA, Intergenic; D019476:Insect Proteins; D042931:Aldehyde Oxidase; D004950:Esterases