Fig. 6

The bistable Ihh switch is robust. a and b and c The bistability area is computed by tracing the Ihh activation and inactivation thresholds (the black curves) when both Gastrin and a second parameters are altered continuously. The names of the second parameters are labelled on y-axis of these panels. d The response of 100 different hosts are computed by randomly changing all parameters and computing 100 one bifurcation diagrams