Figure 7.

Salt-and-pepper pattern of Epi and PrE cells driven by internal noise. Shown is the spontaneous evolution of a population of ICM cells in the same conditions as in Fig. 4, except that internal fluctuations in the number of molecules are taken into account and external noise is absent. Reactions are listed in Table S3 and parameter values are given in Table 1. Ω = 500 and γ_i = 0 for all cells. The color code is the same as in Fig. 4. Stochastic simulations are performed by means of the algorithm of Gillespie (35). As discussed in the text, two cells of the simulated population switch from the Epi to the PrE state and one cell does not pass through an ICM-like state before becoming an Epi cell. To see this figure in color, go online.