Q neuroblasts lineage and the migration properties of the descendants. (A) The position of Q neuroblasts in a cross section of the nematode C. elegans. D, dorsal; V, ventral; L, left; R, right. (B and C) QL and QR neuroblasts lineage patterns, which produce three different neurons and two apoptotic cells (in black and marked by X) are shown. The products of these divisions give rise to ciliated sensory neurons (AQR and PQR), touch sensory neurons (AVM and PVM), and interneurons (SDQL and SDQR). (D) The migration of Q neuroblasts and their descendants in the L1 larva stage. Arrows indicate the migration direction. The time given is the hours after hatching. V1–V6, epithelial seam V1–V6 cells. Bar, 10 µm. (E) Summary of the migration distance and speeds of Q neuroblasts and their descendants. Asterisks denote values derived from the figures of previously published data (see Materials and methods). Other measurements are derived from our time-lapse observations. Carets indicate mean speed ± SEM (number of animals).