Bifurcation analysis of the four synthesis rates. Tristability property of the system when one of the synthesis rates varies. (A) Rate constant a1; (B) rate constant a2; (C) rate constant b1; and (D) rate constant c1. The curves show the value of a model parameter with which the system maintains three stable steady states. (Blue solid line: the steady state with high GATA-1 level; blue dash line: the steady state with high PU.1 level; red solid/dash/dash-dot line is the level of GATA-1/GATA-2/PU.1 in the primed state).