library_construction_protocol: Worms were ground and fixed with EGS solution (final 1.5mM concentration) for 8 minutes, followed by crosslinking with 1% methanol-free formaldehyde for 8 minutes. Chromatin was sonicated to 100-300bp length with a Bioruptor sonicator. 20ug of chromatin was used per IP reaction. The library preparation was performed as previously described (Janes et al. 2018 eLife) using a modified Illumina TruSeq protocol. Briefly, TruSeq adaptors were ligated using NB Quick Ligase (M2200) and libraries were amplified with a KAPA HiFi Hot Start polymerase mix. Aftr PCR amplification, size selection was performed with AMPure beads (Beckman Coulter) to obtain fragments between 250-370bp, and size distribution was validated with a Agilent Tapestation.