Abstract
We propose a generalized Lévy walk to model fractal landscapes observed in noncoding DNA sequences. We find that this model provides a very close approximation to the empirical data and explains a number of statistical properties of genomic DNA sequences such as the distribution of strand-biased regions (those with an excess of one type of nucleotide) as well as local changes in the slope of the correlation exponent α. The generalized Lévy-walk model simultaneously accounts for the long-range correlations in noncoding DNA sequences and for the apparently paradoxical finding of long subregions of biased random walks (length ) within these correlated sequences. In the generalized Lévy-walk model, the are chosen from a power-law distribution P()∝. The correlation exponent α is related to μ through α=2-μ/2 if 2<μ<3. The model is consistent with the finding of ‘‘repetitive elements’’ of variable length interspersed within noncoding DNA.
- Received 6 January 1993
DOI:https://doi.org/10.1103/PhysRevE.47.4514
©1993 American Physical Society