Stochastic models for description of structural-statistical properties in DNA sequences

New stochastic models based on a notion of stochastic codon are proposed. These models, presented by special random strings, describe practical structural-statistical properties which are peculiar to coding DNA both from prokaryotic and eukaryotic genomes. In such the case coding regions are considered as the realizations of random strings. The models introduced explain existence of latent profile periodicity with a period which is not only equal to but also multiplied of three in the coding regions. For the sequences with latent profile period multiplied of three, but not equal to three, the proposed models ensure existence of special property of 3-regularity in these sequences which is practically recognized in all coding sequences of the genomes analyzed. Feasibility of the stochastic models proposed was tested in numerical experiments with binary reencoded paragraphs of literary texts (in English and Italian languages), used as analog of DNA coding regions.