library_construction_protocol: Cells were washed with PBS and fixed in 2mM DSG for 30 minutes and 1% FA for 30 minutes. Fixed Drosophila S2 cells were added at a 1:4 ratio (Dm:Hs) to allow reference normalization. Cells were sonicated to give fragments of 100-300bp followed by IP. DNA libraries were made using the NEBnext ultra DNA library preparation kit for Illumina (Cat no. E7370).