library_construction_protocol: Samples were fixed in 1% formaldehyde solution under vacuum (16% Formaldehyde (w/v), Methanol-free, ThermoFisher) for a total of 12 minutes. After nuclei extraction and lysis, soluble chromatin was incubated overnight at 4ºC with anti-H3K27me1 and anti-H3. Conjugates were immunoprecipitated for 4 hours at 4ºC with protein G Dynabeads™ (ThermoFisher). Libraries were generated using the Ovation® Ultralow V2 DNA-Seq Library Preparation Kit (Tecan), following manufacturer´s instructions. Total ChIPed DNA was resuspended in 10 µL of nuclease-free water and quantified by Qubit HS dsDNA assay (ThermoScientific) before the amplification step. 7 to 16 amplification cycles were used after taking in consideration ChIPed DNA concentration.