Phenotype of the zebrafish bloody minded ( blm ) mutant. A) Mutants can be first recognized at ~27 hpf when signs of malformation in the head are visible (red arrows). At 2 and 3 dpf, eyes are much smaller and the tail is bent dorsally. B) Plastic sections through the eye reveal apoptotic cells in the retina (red arrow) and in the brain at 27 hpf. There is no proper lamination of the retina and necrosis proceeds. Abbreviations: hpf - hours post fertilisation, dpf - days post fertilisation, R - retina, L - lens, PhL - photoreceptor layer, INL - inner nuclear layer, IPL - inner plexiform layer, GCL - ganglion cells layer.