Single centrosome movements are randomized in let-99 embryos and anterior-directed in par-1 embryos. (A) Kymographs from time-lapse sequences of representative embryos. The x axis is a cross section along the AP axis. The y axis indicates time. Bar, 10 µm. (B) Plots of centrosome positions and velocities from kymographs in A. The left y axis gives centrosome position in percentage of embryo length (AP-directed movement) or percentage of embryo height (laterally directed movement). The right y axis indicates velocity. The x axis indicates time from NEB. (C) Mean centrosome peak velocities by direction of centrosome travel. The y axis is velocity. Error bars indicate SEM; lines between columns indicate significance at P = 0.05.