LET-99 is required for spatial asymmetry of cortical pulling forces in zyg-1 embryos. (A) Schematic of centrosome fragmentation analysis in a zyg-1 embryo, as in Fig. 7. (B) Tracking data from representative embryos. (C) Complete dataset from centrosome fragmentation experiments. Tracking velocities (y axis) are plotted against the direction of fragment travel (x axis). Colored bars show the extent of LET-99 and GPR-1/2 cortical domains. (D) Velocity data binned by direction of travel, and averaged for cortical domains. Error bars show SEM; lines between columns highlight statistically significant differences between lateral–posterior and absolute posterior mean velocities in wild type (P = 0.05). The following comparisons were also significant: zyg-1: 0–25 versus 75–100, 0–25 versus 50–75.