Mixed-stage populations were collected by washing off plates with PBS, pelleted in 500 ul of PBS, and flash frozen. Frozen pellets were disrupted by a 7-ml Type B glass Dounce homogenizer, fixed for ten minutes with 1% formaldehyde (diluted from 37% (w/v)) at 37°C and quenched with 125 mM glycine. ChIP samples were processed with a Chromatin Immunoprecipitation Assay Kit (EMD Millipore) according to manufacturer's instructions. Samples were sonicated using a Diagenode Bioruptor UCD-200 at 4°C for 15 minutes on high, with a cycle of 45s on and 15s off. 1/20th of sample volume was taken for input controls. For immunoprecipitation, extracts were incubated overnight at 4°C with 10ul of H3K9me2 antibody (ab1220, Abcam). DNA was extracted by phenol-chloroform and ethanol precipitated. Libraries were prepared by HAIB-GSL (for HiSeq) or GGBC (for NextSeq).