Fig. 5. R1-R6 targeting appears largely normal in sema mutants. Third-instar eye-brain complexes of wild type (A,D), otk³ eye-specific mosaic (B,E), sema-1a^P1 eye-specific mosaic (C) and homozygous mutants (F) were stained with MAb 24B10 (A-C) or with anti-ß-galactosidase antibody (D-F). Individuals in D-F carried the ro--lacZ marker, which labels R2-R5 axons at larval stage. Although sema-1a^P1 caused a defect in the organization of R-cell axons within the lamina (C) that was more severe than that caused by the otk³ mutation (B), it did not significantly affect R1-R6 targeting (compare F with E). Scale bar: 20 µm.