(A-B) Emission ratio of Cdk1 sensor for wildtype embryos (black line), chk1 chk2 embryos (A, green line), and wee1 embryos (B, red line). (C-D) Average Cdk1 activation rate per cell cycle for wildtype (black), chk1 chk2 (C, green) embryos, and wee1 embryos (D, red). Error bars, s.e.m. (E) Log-log plot of Cdk1 speed versus S-phase Cdk1 activation rate for wildtype (black), chk1 chk2 (green), and wee1 (red) embryos. Error bars, 95% CI. (F) S-phase Cdk1 activation rate as a function of DNA content. Inset, cell cycle period, marked from anaphase start time of one cycle to the next, as a function of DNA content. 100% indicates the DNA content of wild type embryos at cycle 13. Error bars, s.e.m. For all graphs, ***, p<0.0001; ns, not significant.