Precipitates were washed sequentially with ice cold low salt wash (0.1% SDS, 1% Triton-X- 100, 2 mM EDTA, 20 mM Tris-HCl, pH8.1, 150 mM NaCl), high salt wash (0.1% SDS, 1% Triton-X-100, 2 mM EDTA, 20 mM Tris-HCl, pH 8.1, 500 mM NaCl), LiCl wash (0.25M LiCl, 1% IGEPALCA-630, 1% deoxycholic acid, 1 mM EDTA, 10 mM Tris-HCl, pH 8.1) and then twice with TE (1 mM EDTA, 10 mM Tris-HCl, pH 8.1). They were then eluted and reverse cross-linked in elution/reverse cross-linking buffer (1% SDS, 0.1 M NaHCO3, 0.2 M NaCl) for 5 hours. Eluted DNA fragments were barcoded with a NEBNext DNA library preparation kit (NEB, Ipswich, MA) and subjected to sequencing on Illumina HiSeq 2000 platform.