ABSTRACT
Nucleotide sequences of intergenic spacer of ribosomal RNA gene cluster (rIGS) were identified in mosquitoes Culex modestus, Culex torrentium and Culex pipiens pallens. The level of interpopulation variability of the rIGS in the subspecies C. pipiens pipiens (form pipiens--mosquitoes that inhabit the open waters, and form molestus--mosquitoes that inhabit basements) living in Russia was estimated. No extensive repetitive sequences characteristic of the rIGS of all previously described species of mosquitoes were found within the rIGS of Culex mosquitoes. At the same time, evolutionarily conserved motifs and relatively short degenerate sequences of different classes of transposable elements, as well as multiple blocks of variable microsatellite repeats were identified. Our data demonstrated that the rIGS of Culex mosquitoes can be considered as a promising molecular marker for the analysis of population and phylogenetic relationships within this group of insects.
Subject(s)
Culex/genetics , DNA, Intergenic/genetics , DNA, Ribosomal/genetics , Genes, Insect/physiology , Multigene Family/physiology , Phylogeny , RNA, Ribosomal/genetics , Animals , Species SpecificityABSTRACT
The results of quantitative PCR (qPCR) presented in the paper clearly demonstrate that the sixteen-fold genome reduction inCyclops kolensisduring chromatin diminution (from 15.3 pg to 0.98 pg) results in a dramatic decrease in ribosomal RNA gene copy numbers in the genome of a somatic cell line by more than two orders of magnitude. The results presented allow for the consideration of the chromatin diminution as a mechanism of rDNA copy number regulation.