The rate and period of daughter centriole growth are not directly determined by the length of S-phase. (A and B) Graphs show the lack of a consistent correlation between the length of S-phase and either the centriole growth rate (A) or growth period (B), in each nuclear cycle. The data were extracted from the data shown in Fig. 3 A and analyzed as described in Fig. 3 C. (C and D) Graphs and charts illustrate and quantify centriole growth parameters in WT embryos and embryos in which either the genetic dose of Cyclin B has been halved to increase the length of S-phase (Ji et al., 2004; CycB^1/2 embryos) or the genetic dose of the S-phase checkpoint protein grapes (Chk1 in vertebrates) has been halved to decrease the length of S-phase (Sibon et al., 1997; grp^1/2 embryos); ≥13 embryos were analyzed in each case. Although S-phase is ∼24% longer in CycB^1/2 embryos compared with grp^1/2 embryos, the parameters of centriole growth are essentially the same in all three types of embryos. Statistical significance was assessed using either an unpaired t test with Welch’s correction (for Gaussian-distributed data) or an unpaired Mann–Whitney test (**, P < 0.01; ****, P < 0.0001; ns, not significant). A.U., arbitrary units. n ≥ 13 embryos for each group; n = 184, 140, and 122 centrioles (mean) from WT, CycB^1/2, and grp^1/2 embryos, respectively. Data are presented as mean ± SD.