Figure 7. eomesa⁺ RGCs regulate phototaxis.

(A) Dotplots showing type-specific expression of melanopsin in larval RGCs. Left: Of five melanopsin homologs (columns), only opn4xa and opn4b have discernible expression in specific larval RGC clusters (rows). Right: opn4xa⁺ and opn4b⁺ clusters include eomesa⁺ RGC types, but not mafaa⁺ or tbr1b⁺ types. An opn⁺eomesa⁻ RGC type is marked by the co-expression of onecut1 and shisa9b. Larval clusters are ordered as in Figure 3A. Expression patterns are conserved in adult RGC types (Figure S7D).

(B) Phototaxis assay. Larvae are placed in a light-dark choice arena, and their positions are tracked over time. A phototaxis index (PI) quantifies attraction towards the light source.

(C-E) Representative traces and PI values of an MTZ-treated control larva (C), ath5⁺ RGC-ablated blind larva (D), and eomesa⁺ RGC-ablated larva (E).

(F) PI values for NTR⁻ Tg(ath5:QF2) and Tg(eomesa:QF2) control siblings as well as ath5⁺ RGC ablated blind fish, and eomesa⁺ RGC-ablated larvae. Shown is a barplot with a superimposed dotplot, where each dot represents one fish. Error bars represent SEM. * p<0.05, *** p<0.001 (Dunn post-hoc test).

(G) Quantification of optomotor response in MTZ-treated controls and eomesa⁺ RGC-ablated larvae, plotted as in F.

(H) Escape probability of MTZ-treated controls and eomesa⁺ RGC-ablated larvae to a looming disc. Each dot represents the mean value at a given stimulus expansion rate. Error bars represent SEM.

(I) Quantification of locomotor activity of MTZ-treated controls and eomesa⁺ RGC-ablated larvae, plotted as in F.