Fig 5. Proposed spatial architecture of D. melanogaster genome.

PCH genomic regions located on different chromosomes coalesce to form the 3D PCH domains, or chromocenters. PCH regions (darker color) and the euchromatic genome (lighter color) form their own separate territories. PCH regions on different chromosomes interact, with inter-arm (2L-2R, 3L-3R) and inter-chromosomal 3^rd-4^th chromosome 3D interactions being more frequent than random expectations. 3D contacts between polymorphic H3K9me2/3-enriched regions in the euchromatic genome (potentially due to TEs, gray bar) and PCH lead to varying 3D genome conformations between individuals (arrows). 3D structures of the euchromatic genome were based on [67] and the positions of PCH regions are inferred from data in Fig 2B.