Generation of mutants with developmental defects in zebrafish by ENU mutagenesis

As a good model for studying early develop-ment of vertebrates, zebrafish (Danio rerio) is attracting more and more attention. Following ENU mutagenesis, 320 F2 families were established. Mutants, which showed defects in epiboly, axis, somite, head, and cardiac and blood systems, were identified by observing morphological changes in F3 embryos. So far, 35 mutant lines have been established, the majority of which showed anomalies in axis and somite for-mation. These mutant lines provide useful genetic resources for cloning of the mutant genes and for studying mechanisms of early development of vertebrate embryos.