Lysates were clarified from sonicated nuclei and histone-DNA complexes were isolated with antibody. Libraries were prepared according to Illumina's instructions . Briefly, DNA was end-repaired using a combination of T4 DNA polymerase, E. coli DNA Pol I large fragment (Klenow polymerase) and T4 polynucleotide kinase. The blunt, phosphorylated ends were treated with Klenow fragment (32 to 52 exo minus) and dATP to yield a protruding 3- 'A' base for ligation of Illumina's adapters which have a single 'T' base overhang at the 3’ end. After adapter ligation library fragments of ~200-500 bp (insert plus adaptor and PCR primer sequences) were band isolated from an agarose gel and DNA was PCR amplified with Illumina primers for 18 cycles. Amplicons were purified with Qiagen QIA Quick MinElute PCR purification kit and libraries were sequenced on the Illumina Genome analyzer or HiSeq2000 following the manufacturer's protocols.