Perturbation of either actin or microtubule dynamics inhibits establishment of cilia polarity. (A–D, left) Representative images from each experimental condition. (right) Circular diagrams of mean cilia orientation (direction of arrow) as well as the variation around that mean (vector length = 1/variance) such that a short arrow represents a cell with high variance, and a long arrow represents a cell with low variance (arrow colors represent data from different embryos). (A) An untreated wild-type embryo at stage 23. (B–D) Embryos treated from stage 23–29 with 0.1% DMSO (B), 10 µM Cyto D (C), or 1 µM Noc (D). (E) Comparison of the average mean vector length (n > 60, >20 cells from at least three embryos). wt, wild type. (F) Quantification of basal body distribution by measuring the distance of individual basal bodies relative to their nearest neighbors (n > 6,000, 100–150 basal bodies from >20 cells in three embryos). (G) Angular correlation analysis for both nearest and farthest neighbor basal body pairs (n > 2,000, 100–150 basal body pairs from five cells in three embryos for each condition). All error bars represent the SD of the mean.