Fig. 3. Abdominal neuroblast lineages lacking Grh activity proliferate for longer than normal. (A,B) Four to five abdominal segments labelled by continuous BrdU treatment from 0-96 hours, showing rows of vm and vl clusters from wild-type control larvae (A) and corresponding but enlarged clusters in grh³⁷⁰ hemizygotes (B). The hemizygotes also show BrdU-positive clusters in ectopic abdominal locations (outlined). (C,D) Confocal projections of one vl cluster containing six cells from a balanced control larva (C) and part of one vm cluster, where nine out of a total of 14 cells are shown from a grh³⁷⁰ hemizygous larva (D; see also Fig. S1 in the supplementary material). BrdU-labelled nuclei are outlined in white. (E,F) Histograms comparing the number of cells generated per vm/vl lineage (from 0 hours onwards) in wild-type larvae and grh³⁷⁰ hemizygous larvae at 72 hours (E) and 96 hours (F). Average lineage size remains at four cells from 72-96 hours in wild-type larvae (72 hours: n=19 lineages, mean=3.9, s.d.=1.5; 96 hours: n=18, mean=4.2, s.d.=1.5) but in grh³⁷⁰ hemizygotes it increases from 7.5 to 14 cells (72 hours: n=14, mean=7.4, s.d.=2.4; 96 hours: n=18, mean=13.7, s.d.=2.4).