Fig. 3. Role of tissue dimensionality for morphogen gradient precision. (A) In a one-dimensional chain of cells, morphogens cannot get beyond the defective cell (red), resulting in a large impact on the gradient. (B) In two-dimensional tissues, the effect of one defective cell is smaller because it can be bypassed (arrows) if morphogen transport is non-directional. (C) In three-dimensional tissues, the effect is even smaller because there are more paths to bypass the defective cell. (D) Logarithmic plot of theoretical (x) calculated for different dimensions, but otherwise identical parameters. Only the target cells are subject to cell-to-cell variability (solid lines), or both the source and the receiving cells (dashed lines). _D/a=7, _D/D₀=0, _k/k₀=1, _j/j₀=0.37 (for details, see Fig. S3 in the supplementary material).