After fixation with formaldehyde, C elegans lysates were clarified from sonicated nuclei and histone-DNA complexes were isolated with antibody. Libraries were prepared according to a modifed Illumina protocol (Ethan Ford's protocol). Briefly, DNA was end-repaired using the NEB ENd repair enzyme Mix. The blunt, phosphorylated ends were treated with Klenow fragment (exo minus, NEB) 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 DNA was PCR amplified with Illumina primers and library fragments of ~250 bp (insert plus adaptor and PCR primer sequences) were size selected with AMPure XP beads.