Fig. 1.

(a) Stochastic calculation of coherence in a system which has mRNA and proteins cooperatively binding to the gene, with coherence given by $2\frac{\sum \mathrm{\Theta }(d\varphi )}{\sum |d\varphi |}-1$ where $d\varphi$ is the difference in angle in mRNA–protein space. (b) Stochastic calculation of the standard deviation of the period distribution divided by its mean. Both colormaps are on the same scale as Fig. 3.