Оценка уровня насыщения последовательности гена субъединицы I цитохромоксидазы С у тлей (Hemiptera: Sternorrhyncha: Aphidoidea) как метод определения относительного возраста таксонов
Aims. DNA saturation effect forms in evolutionary conservative genes as a result of repeated nucleotide substitutions which occur at the same variable loci. In order to find out whether there is a correlation between the level of the DNA saturation in COI gene and the age of taxa in aphids, 340 COI sequences from aphids were compared. Methods. Evolutionary analysis was conducted using the software: MEGA5, DnaSP v5, BioEdit, WebLogo. The DNA saturation level was determined with DAMBE as the transition/transversion ratio for pairs of sequences versus genetic distance. Results. It was found that the DNA saturation effect forms in subfamilies: Lachninae when the genetic distance is 0.03, Eriosomatinae when the genetic distance is 0.08, Calaphidinae when the genetic distance is 0.09. DNA saturation is not registered in subfamily Aphidinae. When constructing the subfamilies phylogenetic cladogram, the subfamilies are arranged according to their evolutionary age. Conclusions. DNA saturation, defined as the shift of the ratio of the observed transitions and transversions in the predominance of transversions, may serve as an indicator of the chronological relationships of taxa.Key words: DNA saturation, transition-transversion bias, COI, aphids.