library_construction_protocol: Drosophila S2 cells were mixed with human cells after collection. Cells were fixed with 1% formaldehyde for 10 min and sonicated using the Bioruptor Pico. Histone H1.2 antibody (Abcam ab17677) was used in immunoprecipitation and ChIP DNA Library preparation was done with NEBNext Ultra II DNA Library Prep kit (cat#E7634L).