Fig. 2

Landscape, barrier heights and switching time.

a-c Landscapes at different morphogen level M (M = 0.5, 0.8 and 1.2 for a, b and c) for the mutual repression with self-activation (MRSA) model. With M increased, left basin becomes more and more shallow, and therefore the switching from left basin to right basin become more and more easy. d-f Average switching time versus noise level separately for different M level (d), different A (e), and different R (f). Every curve (color) is for one parameter set. In (e), the parameter A represents the ratio of the synthesis rate for the two genes, which measures the degree of the asymmetry of the system. Other parameters are set as: k = 0.7, b = 0.7, R = 0.6. In (f), the parameter R represents the strength of the mutual inhibition. Other parameters are set as: k = 0.7, b = 0.7, A = 1.4. g Switching time and barrier heights change with morphogen level M. h Barrier heights versus the switching time.