Fig. 1. Morphogen gradient formation in the presence of cell-to-cell variability. (A) Cellular individuality in the wing disk. The stochastic concentrations of intracellular and extracellular molecules and different cell shapes affect morphogen transport and degradation, independently of the transport mechanism. (B) Gradient formation in a simplified geometry. Concentration profiles for constant (left) or fluctuating (right) morphogen influx j, effective D and k. Average cell diameter, a. (C) One-dimensional lattice model of the scenarios in A. The hopping rates and describe transport between cells n and n+1. They fluctuate about their mean value p₀ because of cell-to-cell variability, as indicated by arrows of different widths. The degradation rate k_n also fluctuates.