Fig. 5. Left-hand six pictures: the anterior domain of lower nuclear densities arises by cycle 11. To facilitate visualization of the anterior domain, and to reduce the impact of the complicating geometry of the curvature at the anterior pole, embryos with a larger anterior domain (from females carrying six copies of bicoid) were scored for the distribution of nuclei (marked by oli-green). Similar results were obtained from the nuclear counts of wild-type embryos (GFP-histone embryo, and data not shown). The numbers represent nuclei counts in a square of constant size (70x70 pixel box) positioned at corresponding points along the AP axis of the embryo. The final image in the fixed embryos series shows Eve stripes (blue). The arrowhead marks the position of the border of the anterior domain, several nuclei to the anterior of the first stripe of Eve. The right-hand six pictures are a time-lapse series of a single embryo carrying a GFP-histone transgene. Owing to differences in magnification from using two different microscopes to capture the images, the same size square yields different densities between the fixed embryo series and the live embryo series, as well as in Fig. 4. Note that the relative difference between the anterior domain and the rest of the embryo is similar. The position of the CF can be seen in the final image of the GFP-histone embryo (gastrulation), and this position can be used as reference point for the AP axis in the other embryos as the same focal plane was kept at all time points.