Plots of average modification level around transcription start sites (TSS).

The x-axis represents- position relative to the TSS set at zero. Positive numbers represent positions downstream of the TSS, while negative numbers are upstream. The y-axis indicates the average histone modification enrichment log ratios. Black dots represent points statistically significantly different (p-value<0.01 wilcox rank sum test) than the corresponding point in the other curve. Forpanels (a, b, d and e) the blue line represents TSS at least 3000 bps away from the center of a hot spot, log ratios were binned in 200-bp windows and the average for each bin plotted. The black line represents genes with the center of a hot spot located within 500 bp upstream of the TSS,log ratios were binned in 200-bp windows and the average for each bin plotted. For panels (c and f) the black line represents the average histone modification in genes which entirely contain a cold spot (for definition of cold spot see Methods). The blue line represents the average histone modification in genes which do not overlap to any extent a cold spot. Plots were produced by binning histone modification log ratios in bins proportional to gene size (each bin was 1/10 the size of the given gene) the average for each bin is plotted.