Figure 2. Precision and reproducibility of cytoplasmic hb profiles.

A: Absolute cytoplasmic hb mRNA counts per standardized volume as a function of AP position. Data for four embryos at nuclear cycle 12 (blue), 13 (green), early 14 (red), and late 14 (magenta). Position is shown as distance from inflection point x_transition (see also Figure S3C). Inset: fractional SD σ^max/N^max in the spatial domain of highest mRNA accumulation as a function of the mean count (N^max) for 101 embryos. Dashed line at 8%. B: Cytoplasmic hb mRNA counts (N^max) as a function of time. Ages estimated by visual inspection of DAPI staining; relative width of mitoses (gray shading) and interphases according to Alberts and Foe (1983). Reproducibility of counts in 12^th and 13^th mitoses is 8% and 11%, respectively. Inset: estimated reproducibility $\widehat{\sigma }$ as a function of time. Data points: running averages of root-mean-square displacement from smoothed timeline over 15 consecutive data points normalized to mean. Dashed line: average $\widehat{\sigma }$ (17%). See also Figure S3