Comparative characteristics of the intergenic spacer of the ribosomal RNA gene cluster in mosquitoes of the genus Culex (Diptera: Culicidae)

The intergenic spacer of the ribosomal RNA gene cluster (IGS) was sequenced for mosquitoes Culex modestus, C. torrentium, and C. pipiens pallens. The interpopulation variation of the IGS was estimated for the C. pipiens pipiens forms pipiens, which inhabits open waters, and molestus, which inhabits basements, of Russia. The IGSs of the Culex mosquitoes were not found to contain extended repetitive sequences characteristic of all known mosquito IGSs. At the same time, evolutionarily conserved motifs, relatively short degenerate sequences belonging to various classes of transposable elements, and multiple blocks of variable microsatellite repeats were identified. Based on the results, the IGS of the Culex mosquitoes was assumed to provide a promising molecular marker for population and phylogenetic analyses of the group.