Cloning of fish zinc-finger genes related to Krox-20 and Krox-24.

Southern hybridization suggests that the zebrafish genome contains multiple zinc-finger genes related to the putative mouse developmental genes, Krox-20 and Krox-24. The polymerase chain reaction was employed to amplify and clone the zinc-finger regions of genes related to Krox-20, from two fish species and, for comparison, mouse, hamster and fox. DNA sequence analyses suggest that the genes cloned include the guppy homologue of Krox-20 and the zebrafish homologue of Krox-24, and that these genes diverged prior to the separation of the lineages leading to teleosts and to mammals.