Genetic Differentiation and Evolutionary Transition-Transversion Bias in Vertebrates by the Example of the CYTB Gene with Emphasis on Mammals and Primates

A negative answer to the question about the reducibility of genetic processes at the level of macroevolutionary events to microevolutionary ones has been obtained by analyzing the evolutionary transition-transversion bias and estimating the rates of molecular transformations in a number of vertebrates by the example of the CYTB gene. As a result, it has been established that, at a divergence at a level below families, the frequency of transitions sustains “a jump,” due to which the rate of molecular evolutions increases by an order of magnitude, whereas there occurs a slight predominance of transversion frequencies with a synchronous linear increase in the frequency of different nucleotide substitutions at the levels of orders and higher. An obvious reason for distinctions between the genetic processes of micro- and macroevolution is the leading role of spontaneous mutations in the formation of species. Their canalization results in stable morphological distinctions formed during postnatal ontogenesis. At the same time, the stages of macroevolution are associated with the transformation of organogenesis to be fixed with by changes in the sets of genes governing the nature of gene regulation and the interaction of genes in development.