1/f correlations in viral genomes--a Fast-Fourier Transformation (FFT) Study.

We have studied the presence of long-range correlations in the complete genomes of ten different dsDNA viruses and Saccharomyces cerevisiae (bakers' yeast) chromosome I. We have also studied the correlation between the distribution of the gene length and the domain of "1/f region" of their genomes. Linear regression analysis was done for the power-law region of these organisms and the slope values obtained were approximately -1, which signify the existence of "1/f noise" in the low and medium (intermediate) frequency regions. This suggests the presence of long-range correlations in their genomes. The presence of 1/f noise in a given frequency interval indicates the existence of a fractal (self-similar) structure in the corresponding range of wavelengths. The results of our study suggest that genes have correlations within themselves, and the correlations appear to be related with the scaling exponent alpha.