Cells were sorted into PBS and fixed with 1% formaldehyde. MicroChIP was performed using TrueMicroChip kit (Diagenode) according to manufacturer instructions with following modifications. For each replicate, ~20,000 cells were pooled together with 1 million Drosophila Kc167 cells and processed using Covaris E220E sonicator at peak power 140, duty factor 5, 5 cycles/burst, 20 min per sample. The sonicated samples were then cleared by 10 min centrifugation and mixed with 20 µg antibody (anti-H3K27me3, Cell Signaling 9733), and incubated overnight with rotation at 4ºC. Complexes were pulled down using Protein A Dynabeads (ThermoFisher Scientific), washed and de-crosslinked with kit buffers, and DNA was isolated using standard phenol-chloroform procedure. Libraries were prepared using MicroPlex Library preparation kit (Diagenode), with 8 cycles of amplification