**Figure 6.** Simulated (*CycE/Cdk2-a*) and measured (EdU) time series of cells at G1-S transition for (**A**) 5 Gy IR, (**B**) 10 Gy IR and (**C**) 20 Gy IR, respectively. Thick black line: simulated *CycE/Cdk2-a* using the parameterized model (Figures 3, S4). Thin gray lines: Monte-Carlo simulation (MCS) of *CycE/Cdk2-a* using the parameterized model. Thick red line: Average MCS. Red shaded region: Standard deviation of MCS. Dots: Measured mean relative EdU incorporation ± SEM (n≥3).