Nuclease accessible regions tend to be long, e.g. 10 kb or longer. This was clear even in the early papers on DNase sensitivity (mid-to-late 1970's; Groudine and Weintraub). These accessible regions can contain entire genes or even clusters of genes. Within the nuclease accessible regions, some localized DNA segments are so readily cleaved that double-strand breaks are generated at that position in a substantial fraction of the cells in the population. These are the DNase-hypersensitive sites (DHSs) first mapped by Carl Wu (late 1970's). We see the Fseq "regions" as the equivalent of nuclease accessible regions, and the Homer "peaks" as the equivalent of DHSs.
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