Fig. 2

The 3D genome’s hierarchical organization. Chromosome territory refers to the region of the nucleus occupied by chromosomes. The entire genome can be partitioned into two multi-MB spatial sections, which can be called “A” and “B” compartments. There are frequent intracompartmental interactions, while there are fewer intracompartmental interactions. “A” compartments: open chromatin that is highly expressed and gene-rich, and has a high GC content, as well as histone indicators for active transcription, and is frequently found in the nucleus’s interior. “B” compartments: closed chromatin with inactive expression, gene deficit, and compact structure, carrying histone markers of gene silence, and located on the nucleus’s periphery. Topological domains are areas of the genome that interact with one another more frequently in chromatin compartments (TAD). These areas are conserved in various cells of different animals and are rich in CTCF and adhesive proteins, and CTCF, cohesive proteins, and mediators mediate the creation of enhancer promoter rings in these locations