Human genomic DNA was obtained from Promega (#G1521, female) The genomic DNA was digested with the restriction enzyme SbfI-HF (New England Biolabs, R3642L). For each of two replicates, 25 μg of DNA was digested with 200 units SbfI-HF in a 500 μl reaction at 37 °C overnight. The digested DNA was run on a 1% agarose gel and fragments corresponding to 2-2.5 kb, 2.5-3 kb, 3-4 kb, and 4-5 kb were excised. All fragments from replicate 1 and the 3-4 kb fragment from replicate 2 were purified using the QIAquick gel extraction kit (Qiagen). The purified products were concentrated using the Zymo DNA clean & concentrator kit. Finally, tagmentation and library preparation were performed following the standard bulk ATAC protocol, using the same ratio of DNA mass to Tn5 when a lower amount of DNA was recovered after size selection.