Nucleosome formation potential score distributions for 5' regions of housekeeping and tissue specific genes. The 5' sequences of human housekeeping and tissue specific genes were analysed by Recon for distribution of nucleosome formation potential scores. Frequency distribution histograms were plotted for scores in various intervals (range -3.2 to +3.2). (A) and (B) show the distribution of nucleosome formation potential scores at 400 and 2000 bp upstream from the gene start site respectively. Nucleosomal density is significantly lower for housekeeping genes as compared to tissue specific ones, in regions close to the gene start site.