An improved distribution of codon frequencies allowing for inhomogeneity of DNA's primary-structure evolution.

This is a sequel to the paper, where a model which describes ranged series of codon frequencies was proposed. The model was tested against the empirical distributions obtained for the best studied species and was on the whole found to be in fairly good agreement with the available data. The few deviations from the model's predictions were found to have a monotypic regularity. In the present paper we proceed on the assumption that the deviations are due to inhomogeneous conditions of molecular evolution within a genome. This approach makes it possible to elaborate the theory presented earlier. An improved model is derived for the ranged distribution of codon frequencies, which is then tested against the experimental data.