Fig. 1

Organizational layers of chromatin and their reflection in Hi-C maps. Organizational layers of the chromatin fiber in the cell nucleus (top) aligned with the representation of those features in Hi-C interaction maps (bottom). Chromosomes reside in distinct territories with little intermingling. Therefore, chromatin contacts occur predominantly within the same chromosome (left panels). Within the chromosomes compartments with different chromatin properties (A compartment—active chromatin, B compartment—inactive chromatin) can be observed that interact with regions belonging to the same compartment type (blue box) (middle panels). Underlying these features in the folding of the chromatin fiber into chromatin loops, to a large extend mediated by the cohesin complex and CTCF, visible in the 1 Mb region shown for chr19 as regions with strong interactions (right panels). (Hi-C maps were generated using data for HCT116 cells by Rao et al. 2017 [5] and Juicebox.)