Characterization of a toggle triad. (a) Frequency of monostable, bistable and tristable solutions for a toggle triad. (b) (i) Heatmap showing the all solutions for a toggle triad; (ii) the nomenclature shown capitalizes the node whose levels are relatively high. Thus, Abc denotes (A-high, B-low, C-low), aBc denotes (A-low, B-high, C-low), abC denotes (A-low, B-low, C-high) (three ‘single positive' states). ABc denotes (A-high, B-high, C-low), AbC denotes (A-high, b-low, C-high), and aBC denotes (A-low, B-high, C-high) (three ‘double positive' states). ABC denotes (A-high, B-high, C-high) (triple positive), abc denotes (A-low, B-low, C-low) (triple negative) states. (c) Frequency of 8 = (23) possible monostable solutions. (d,e) Frequency of different bistable and tristable cases; with the most frequent ones being combinations of Abc, aBc and abC = {Abc, aBc}, {aBc, abC}, {abC, Abc} (bistable) and {aBc, Abc, abC} (tristable). Error bars represent the standard deviation over n = 3 independent replicates of RACIPE. *: p < 0.05 for Student's t-test.