BIRD, N.C.*; MABEE, P.M.: Development of the Axial Skeleton in the Zebrafish, Danio rerio

Although the zebrafish, Danio rerio, is used extensively as a model organism for genetic and developmental studies, no data on the developmental morphology of the vertebral column and associated structures are available. Using whole mount staining we are developing a baseline for the development of skeletal structures in the axial skeleton (centra, vertebral spines and arches, radials, fin rays, hypural complex, supraneurals, Weberian apparatus) of the zebrafish in order to pinpoint lengths/ages in which specific structures are developing. Furthermore, we are raising zebrafish mutants (e.g. finless, fused somites) with documented vertebral or fin abnormalities for comparison with wildtype development. Data collected from mutants may help clarify specific gene function, and allow for gain of function expression tests to restore wildtype condition. We are also using immunohistochemistry to uncover the pattern of radial muscle innervation in the dorsal and anal fins. These data will be compared with those from other phylogenetically relevant fishes to help elucidate the modular evolution of the median fins. Images of our data are currently being uploaded to the Zebrafish Information Network website (http://www.zfin.org).