Molecular comparisons of the Culex pipiens (L.) complex esterase gene amplicons
Buss, D. S. and Callaghan, A. (2004) Molecular comparisons of the Culex pipiens (L.) complex esterase gene amplicons. Insect Biochemistry and Molecular Biology, 34 (5). pp. 433-441. ISSN 0965-1748
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To link to this item DOI: 10.1016/j.ibmb.2004.02.002
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. (C) 2004 Elsevier Ltd. All rights reserved.