(C - F) Quantification of the QR.ap migration angle (C D), distance (E) and speed (F) in mig-2S139A/E mutant animals. Each line in (C  E) represents the measurement from one movie of QR.ap migration. Error bars indicate SD. N = 12 -17. **, P 0.01; ***, P  0.001 by Student's t tests. 