Micro-dissected GT (35 to 40) or CR (70) were crosslinked in 1% formaldehyde/PBS for 20 min and stored at -80oC until further processing. Chromatin was sheared using a water-bath sonicator (Covaris E220 evolution ultra-sonicator). Immunoprecipitation was done using the following antibodies, anti-CTCF (Active Motif, 61311), anti- H3K27ac (Abcam, ab4729), and H3K27me3 (Merck Millipore, 07-449) Libraries were prepared using the TruSeq protocol, and sequenced on the Illumina HiSeq system (100bp single-end reads) according to manufactures instructions.