Lysates were clarified from sonicated nuclei and histone-DNA complexes were isolated with antibody. (1) DNA fragment：Adjust the volume of the combined gDNA sample to a total volume of 41 μl using 1x TE and fragment the DNA to 300 bp using the Disrupter. (2)End repair: Blunt-ended fragments are created by filling in or chewing back 3' and 5' overhangs. Phosphorylation of the 5'ends ensure the fragments are suitable for ligation. (3)dA-Tailing: This step is dA-tailing of the 3'end of the end-repaired, phosphorylated fragments. This single A overhang enables ligation to adaptors with single T overhangs. (4)Adaptor ligation: Adaptor containing sequences required downstream in the sequencing workflow are ligated to the dA-tailed fragment. (5)PCR amplification: The KAPA HiFi DNA Polymerase has been inactivated, enabling amplification of DNA. (6)2% agarose gel select the fragment 200~500bp.