Fig. 1: Linage dependent repulsion in the larval medulla.

a, b Schematics of the developing Drosophila medulla in L3 larval stage. Lateral (a) and dorsal (b) views. The dotted line in (a) indicates the plane showing the columns in the medulla layer. The dotted lines in (b) indicate the planes showing the NB and neuron layers. b, c Schematics of the proneural wave and temporal transcription factors. d, e Neurons of the same lineage are visualized by elav-Gal4 MARCM clones (GFP, white). Dpn (red) and Ncad (blue) visualize the NBs and neuropil, respectively. n = 26 in (d). n = 21 in (e). f, g The medulla structures visualized by Ncad (blue). f M0 and medulla layers in a lateral view. g The medulla columns in an anterior view. h–k Neurons of the same lineage are visualized by drf-Gal4 twin-spot MARCM clones (GFP in white, RFP in magenta). Ncad (blue). Sister neurons reroute in M0 layer, and innervate different columns in the medulla layer. Arrows and arrowheads indicate arborizations in the medulla layer and cell bodies, respectively. l A histogram showing the distance between pairs of neurons on the surface of the medulla layer (n = 110). 0 μm indicates fused indistinguichable pairs. m A box plot of the distance between distinguishable 110 pairs of neurons in 38 clones found in 38 independent brain samples. The cases of 0 μm distance are not included. Center line, median; box limits, upper and lower quartiles; whiskers, 1.5× interquartile range. Median and average are 5.78 and 8.50 μm, respectively. Source data are provided as a Source Data file. n, o Projections of medulla neurons in early L3 larval stage visualized by elav-Gal4 MARCM clones (GFP in white). Ncad (blue). n 0–32 h L3 larva only showing M0 layer (n = 20). Neurites are already defasciculated within M0 layer. o 32–48 h L3 larva showing M0 and medulla layers (n = 49). Neurites are defasciculated in M0 layers and innervate the medulla layer. d–f, h–k, n, o Lateral views showing the neuron layer in (b). g Anterior view showing the columns along the dotted line in (a). Scale bars indicate 20 μm in (d, f, n, o) and 5 μm in (e, g, h–k).