Diffusion coefficients of two-dimensional viral DNA walks.

DNA sequences are represented as two-dimensional walkers based on groups of mapping rules for the nucleotides in the DNA sequences. Digital sequences from irrational and random numbers in base 4 are generated and their diffusion properties are then compared with those of 21 nucleotide sequences of animal and plant viruses. By defining the diffusion coefficient as a function of the number of steps taken in a walk, we show that the coefficients for the viral DNA sequences generally have maximum values considerably larger than those for the random-number sequences of same lengths. Moreover, using the walker diagrams generated by different mapping groups, we can study the dominance of any of the nucleotide pairs (AG or CT), (AC or GT), or (AT or CG) in a DNA sequence. Other possible studies of this approach are mentioned.