Fig. S1

Isthmic gene expression, related to Figure 1. (A) Manders’ colocalization coefficient (MCC) quantifying overlap of markers in the larval isthmus. This data shows all pairwise comparisons between single brains with mean values shown in Figure 1H. p-values correspond to comparisons of MCC for chata+vachta versus chatb+vachtb and the corresponding upper labels (Tukey’s HSD correction for multiple comparisons following 2-way ANOVA). (B) MAPK expression in the isthmus showing the large cerebellar fascicle (white arrows) adjacent to and crossing chata expression. Scale bar, 25 mm. (C-K) Registered expression of markers used to characterize the larval isthmus. (C-H) show maximum-intensity projections across the entire dorso-ventral extent of the brain (325 mm), while (I-K) show projections across a smaller dorso-ventral region at the level of the isthmus (90 mm). All images show median intensity across registered datasets. Scale bar 100 mm. (L) Single focal plane from a triple fluorescent in situ of a 6 dpf larval brain detecting chata, vachtb and gad1b mRNA in the right isthmus. Almost no overlap is observed between these markers. Scale bar, 20 mm.