Histology of retinas from old (two-year-old) male myoc transgenic zebrafish. Tissue sections were stained with hematoxylin-eosin. Variable retinal disorganization and dysplasia, ranging from (A,F) the presence of a neuroretinal mass to (B,D,G,I) different degrees of photoreceptor degeneration and increased number of nuclei in different layers or (C,H) no evident alterations. Control wild type retina (E,J). Head tissue sections in the inserts indicate the localization of the images shown in the different panels. The images are representative of two individuals per phenotype. Arrows: chondrocytes in the scleral cartilage. Scale bars: 50 μm. Only clearly identifiable retinal layers are indicated. GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; LE: left eye; OA: ocular alterations; OPL: outer plexiform layer; ONL; outer nuclear layer; PHL: photoreceptor layer; RE: right eye; RFL: retinal fiber layer; Tg/+: transgenic; +/+: wild type.