The zebrafish (Danio rerio) has received considerable attention as a m
ainstream model for the molecular and genetic study of vertebrate deve
lopment. In our laboratory, we have conducted a third-generation scree
n of chemically mutagenized zebrafish for recessive mutations affectin
g the visual system. This report describes the visible phenotypes and
number of morphological mutants so far observed and presents a more de
tailed histological analysis of six of these mutations. Through analys
is of mutant larvae, it was determined that several of the subtle morp
hological mutations resulted in degeneration of specific cellular laye
rs of he retina. Other mutations resulted in some degeneration distrib
uted diffusely across the entire retina or concentrated at the retinal
margin. A single mutation affecting invagination of the optic cup and
lens vesicle Formation resulted in a failure to develop an anterior c
hamber. These results demonstrate the utility of a small-scale, highly
focused screen for uncovering novel loci involved in retinal and eye
development. (C) 1997 Wiley-Liss, Inc.