Fig. 5. Simulation of mutations. Simulations were conducted as in Fig. 1, except that at time 0, the rate of transcription of each of the respective genes was set to zero, and the model was simulated for an additional 1,500 h to allow the model to reach its steady state. If just one CRY1 or CRY2 gene copy was present, and no copies of the other, CRY1 or CRY2's rate of transcription, respectively, was halved, in addition to setting the rate of transcription of the other CRY to zero.