Evolutionary transition-transversion bias by the example of the cytb gene of palearctic Muridae (Rodentia) and Vespertilionidae (Chiroptera)

A comparative analysis of the features transition-transversion bias nucleotide sequence cytb gene in microbats (Vespertilionidae, Chiroptera) and mice (Muridae, Rodentia) shows both general regularities certain family-level features. common feature two families is fact sharp predominance transitions over transversions at early stages evolutionary process, followed by equalization ts/tv-displace- ment species genus levels divergences, as well that increase frequency phyletic lineages gradual, transition intermittent. At same time, spontaneous mutations drift, rate ts/tv drift compensation, are specific to families. These circumstances do not make it possible obtain comparable estimates divergence different phyla cause insurmountable difficulties creating a universal formula for molecular clocks.