The schematics of 3D genome folding on 2D heatmaps. Loops, the puncta signals between two or more loci are shown as the corner dots, and the triangular shapes of the domains represent TADs. Those smaller domains within the TAD that may or may not share the boundary are called subTADs or nestedTADs. The stripe signals along the boundary of TADs represent loop extrusion, as the interactions are continuously made along the extrusion process. Compartments A/B are illustrated as the checkerboard or plaid pattern in the zoomed out heatmap (right). The huge rectangular shapes of the alternating signals illustrate that compartment A binds to other compartments A, and vice versa.
