Figure 3 : The lower limit of the lifetime divisional load as a function of the number of hierarchical levels.

From: Hierarchical tissue organization as a general mechanism to limit the accumulation of somatic mutations

Figure 3

The black and grey solid lines (with filled circles at integer values of n) show the lower limit of the lifetime divisional load of a tissue, D*, as a function of the number of hierarchical levels, n, for n≤log2(N) and n≥log2(N), respectively. The theoretical minimum, log2(N), achievable by a series of divisions along a perfect binary tree characteristic of non-renewing tissues, is displayed with a dashed line. Here we have assumed N=3 × 108 roughly corresponding to the number of cells shed by a few square millimetres of human skin that is sustained by a single stem cell.