Figure 10.

Replication timing and the tissue-specific “heterochromatin code” in a coordinate system for two different cell types (arbitrary hepatocytes and lymphocytes). (a) Hypothesis: The tissue-specific positional information is created by the latitude positions of silencing constitutive heterochromatin (CHR) clusters set (designed as red and blue balls) by replication timing upon the radial chromosome longitudes as the “3–4 D address” (to be specified by topology-associated domains (TADs)). (b) Principle sketch of the CHR clusters positions in the cell nucleus in a radial-concentric “geographic map” of coordinates (on 2D image) determined by Delaunay triangles. Nl—nucleolus.