Zebrafish Make a Big Splash

Thus, the most efficient way to find genes that have key regulatory functions in vertebrate development is Institute of Neuroscience 1254 University of Oregon to screen for them directly by looking for their mutant phenotypes during embryogenesis. Eugene, Oregon 97403–1254 Two groups have now completed the most extensive genetic screens ever carried out in a vertebrate to isolate mutations in genes affecting embryonic development of The world of developmental biology was changed for-This effort has been a tour de force by the laboratories ever in October 1980 by a paper demonstrating that of Christiane Nü sslein-Volhard at the Max Planck Institü t genes required for embryonic development could be in Tü bingen, Federal Republic of Germany, and Wolf-revealed by systematic searches in Drosophila melano-gang Driever at Massachusetts General Hospital and gaster (Nü sslein-Volhard and Wieschaus, 1980). Seven Harvard Medical School in Boston, Massachusetts. months later, a paper suggesting that similar ap-They were joined in this effort by members of several proaches could be taken in Danio (Brachydanio) rerio other laboratories, especially those of Nü sslein-Vol-appeared in the same journal (Streisinger et al., 1981). hard's colleague Friedrich Bonhoeffer and Driever's col-The article on fly mutations had historic consequences. league Mark Fishman. These screens involved 65 people The article on zebrafish received considerably less at-who examined over a million and a half embryos over tention. However, during the last fifteen years, the world about a two year period. Both screens used similar of developmental biology has become increasingly strategies: the F3 progeny of fish carrying chemically-aware of the zebrafish as an experimental organism induced point mutations were examined under the ste-for understanding vertebrate embryonic development. reomicroscope for alterations in a long list of morpholog-Today, the genetic potential suggested earlier is about ical features. Together, these screens resulted in the to be realized by the publication in the December 1996 isolation and initial characterization of an impressive issue of Development of 37 papers describing mutations 1858 mutations affecting almost every aspect of embry-in genes that affect nearly every aspect of zebrafish onic development (Table 1). bryology were elucidated by classical experiments in Sagerströ m et al., 1996) to examine how mutant genes amphibian and avian embryos early in this century. How-alter embryonic signaling. Finally, genome mapping is ever, an understanding of the underlying mechanisms now extensive (Postlethwait et al., 1994; Johnson et al., has been hampered by the inability to carry out genetic …