Publication Date:
2011-08-24
Description:
We propose a generalized Levy 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 alpha. The generalized Levy-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 lj) within these correlated sequences. In the generalized Levy-walk model, the lj are chosen from a power-law distribution P(lj) varies as lj(-mu). The correlation exponent alpha is related to mu through alpha = 2-mu/2 if 2 〈 mu 〈 3. The model is consistent with the finding of "repetitive elements" of variable length interspersed within noncoding DNA.
Keywords:
Life Sciences (General)
Type:
Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics (ISSN 1063-651X); Volume 47; 6; 4514-23
Format:
text
