Fig. 6. A perpendicular cleavage plane division giving asymmetric fates. (A) A cell (white dashed outline) divides with a perpendicular cleavage plane (pink broken line) to generate a neuron (red outline) and a progenitor (green outline). Apical processes of both daughter cells are visible as their nuclei migrate back to the basal surface (blue broken line). The nucleus of one cell (red outline) reaches the basal surface first and starts to withdraw its apical process, whereas its sibling (green outline) continues back to the apical surface and divides again; the differentiating daughter cell (red outline) is photobleached in the last frames. Scale bar: 10 µm. Each image is a MIP through 30 z-sections taken at 1.5 µm intervals. (A') Lineage tree for A. (See Movie 5 in the supplementary material.) (B) Dot plot showing cleavage plane orientations of all cells, the progeny of which could be followed to subsequent division or terminal differentiation.