A Method for Evaluating the Feasibility of Chargaff's Second Rule. Testing the Rule on Bacterial Chromosomes

In 1979, Chargaff published a mathematical formulation of his second rule, which states that in each of the complementary strands of two stranded DNA, the amount of adenine is equal to the amount of thymine and the amount of guanine is equal to the amount of cytosine. This rule has now been tested on numerous groups of sequences belonging to various organisms and, with a small number of exceptions, has been confirmed in most cases, but the conclusions about the feasibility of the rule are qualitative rather than quantitative. To our knowledge, no large-scale tests of the rule on bacterial genomes have been carried out. In the proposed work, the rule is tested on 38830 non-degenerate bacterial sequences extracted from the NCBI GenBank 2023 repository. We perform a more complete statistical analysis of the feasibility of the rule in bacterial genomes than is customary in the literature. A new approach to assessing the validity of the rule is proposed.