Mosaic organization of DNA nucleotides

Long-range power-law correlations have been reported recently for DNA sequences containing noncoding regions. We address the question of whether such correlations may be a trivial consequence of the known mosaic structure (''patchiness'') of DNA. We analyze two classes of controls consisting of patchy nucleotide sequences generated by different algorithms-one without and one with long-range power-law correlations. Although both types of sequences are highly heterogeneous, they are quantitatively distinguishable by new fluctuation analysis method that differentiates local patchiness from long-range correlations. Application of this analysis to selected DNA sequences demonstrates that patchiness is not sufficient to account for long-range correlation properties.