Total genomic DNA was extracted from CNS and disc materials using XXX. Invitrogen Dynabeads (M-280 sheep anti-rabbit IgG) were used for Chromatin immunoprecipitation in place of protein A or G agarose/salmon sperm DNA beads. ChIP reactions were performed with 1:100 dilutions of anti-Pho (Brown et al., 2003), anti-Spps (Brown and Kassis 2010), anti-Ph (Donna-Arndt-Jovin), 1:200 dilutions of anti-E(z) (rabbit polyclonal raised against bacterially expressed full length E(z)), anti-Psc (Nicole Francis), anti-Pc (Santa Cruz Biotech Inc, sc25762), and anti-H3K27me3 (Millipore, 17-622).