Fig. 9

Comparative expression of dscam and sdk genes in the central inner retina of developing zebrafish at 96 hpf. Dual in situ hybridizations show comparative expression domains of CAM genes. A) dscama and B) dscaml1. C: Merged image reveals some co-expression within the INL (boxed region). D: sdk1b is expressed in a subset of cells within the basal INL. E: dscamb was also observed in the basal INL. F: The merged image shows some overlap in expression (boxed region). G: sdk2b expression was observed within the INL (boxed region). H: dscamb transcripts were also observed in the INL, and I: merging the two reveals low levels of co-expression (boxed region). J: sdk2b is expressed in a subset of cells within the INL. K: sdk1b expression is also observed in cells in the INL. L: The merged image reveals that some overlap exists between cells positive for both. For all comparisons, we observed a mosaic of cells expressing the two targeted transcripts—some cells that express both transcripts and other cells that express only one or the other. Dashed boxes show the identical region of interest (ROI) in each row. The red boxes correspond to the ROI for panels showing single-label expression in A, B, D, E, G, H, J, and K. White boxes in C, F, I, and L show ROIs of co-expression of paralogs. Abbreviations: hpf=hours post fertilization; Dscam=Down syndrome cell adhesion molecule; Sdk=sidekick; INL=inner nuclear layer; GCL=ganglion cell layer. Scale bar in A=20 μm (applies to all).