Figure 3.

Oscillations in Hes/Her protein numbers for the simplified two-cell gene regulatory system with Delta-Notch coupling. The system parameters are identical to figure 2, but here $r_{hd}^{\mathrm{h}}=0.9$ and $r_h^{\mathrm{h}}=0.1$, i.e. the coupling between the two cells has been increased (see electronic supplementary material, S1). As a result, the oscillations in the individual-based system are more clear, periodic and synchronized. This is further demonstrated by the corresponding power spectra in figure 4c2. Again, the deterministic trajectory poorly reflects the dynamics of the individual-based system. (Online version in colour.)