Fig. 2.

Quantitative evaluation of Bcd gradient scaling. (A,B) Shown are Bcd intensity differences, ΔB, between the large and small embryos as a function of x (A) or x/L (B). ΔB is calculated by subtracting the mean B of line 9.31.2 from the mean B of line 2.49.3, and normalizing to averaged B, ⟨B⟩. (C,D) Shown are differences in positions, Δx, at which mean Bcd gradient profiles cross given thresholds, plotted as a function of x (C) or x/L (D). For panel C, Δx is normalized to the average length of both embryos ⟨L⟩, and ⟨x⟩ denotes averaged position at which the mean profiles cross a threshold. Interpolated mean profiles were used to obtain x at arbitrary B thresholds chosen. Error bars are s.d. of the difference between the sample means (Cheung et al., 2011). (E) Scaling coefficient S as a function of AP position in the large and small embryos. This analysis was performed as described previously (de Lachapelle and Bergmann, 2010; Cheung et al., 2011). Error bars shown represent 95% confidence intervals from linear regression (Cheung et al., 2011).