Fig. 5

Two dimensional simulations for the boundary sharpening effects over time at different gene expression noise level d for the mutual repression model. Blue: X is expressed, red: Y is expressed. a for d = 0, b for d = 0.01, c for d = 0.02 d-f The landscape for the mutual repression (MR) model at different M level (M = 0.2 for D, M = 0.4 for E, and M = 0.8 for F). Red X and Y separately indicate the X and Y attractors. g Switching time and barrier heights change with morphogen level M. h Barrier heights versus the switching time. i Average switching time versus noise level for mutual repression model at different A. Parameter A represents the ratio of the synthesis rate for the two genes (gene B/gene A), which measures the degree of the asymmetry of the system. Other parameters are set as: R = 1, k = 1, b = 1. j Diagram for the mutual repression model