FIG. 1.
Parabolic and nonparabolic background forms. Representative parabolic (A) and flat (B) backgrounds. Data were taken from the middle 45–55% egg length of embryos. In general, we observed parabolic background for flatter embryos. Embryo cross-sectional radii were measured and classified as flattened (14–23 μm) or round (24–33 μm). Considerable variability in curvature was noted, but flatter embryos tended to exhibit higher curvature overall. Data were obtained for Giant imaging ventral–dorsal (C) and anterior–posterior (D), and lacZ imaging ventral–dorsal (E) and anterior–posterior (F). Parabolicity of background is measured by curvature of the parabola fit to curve, with apex generally at center of embryo cross section. For anterior–posterior Giant background measurements, young gtX11 mutants expressing virtually no detectable Giant protein were used. For lacZ background imaging embryos without the reporter gene were utilized.