After sequencing human libraries, we often find that approximately ½ of reads are of sub-nucleosomal length (less than approximately 150 bp) and approximately half of the reads longer than this length (Figure 2c). In general we find excellent agreement with DNase-seq methods and enrichment for regions of accessible chromatin, with ~20% of reads concentrated in ~2% of the genome. We estimate that a single 50 ul reaction volume can generate approximately 50–100M unique amplifiable fragments.
