Histogram of cluster length for HeLa sample. Clusters with IDR ≥ 0.1 or longer than 200 bp were discarded. Clusters were binned according to their size, and the number of clusters for each size was plotted on the graph. Within each size bin, the clusters containing 1 to 40 clusters (i.e., “clusters within clusters”) are shown in pink, containing 41 to 80 clusters are yellow, and so on (see legend at right of the figure). The frequency of clusters in each size bin is represented in the log (base 2).