This Program Announcement (PA) is to encourage investigator-initiated applications designed to exploit the power of the zebrafish as a vertebrate model for biomedical and behavior research. Applications proposing to develop new tools or genetic or genomic resources of high priority to the zebrafish community that will advance the detection and characterization of genes, pathways, and phenotypes of interest in development and aging, organ formation, behavior, and disease processes are welcome. This effort stems from an NIH initiative developed by the Institutes and Centers of the Trans-NIH Zebrafish Coordinating Committee under the co-chairmanship of NICHD and NIDDK. Since its formation in 1997, the committee has played an active role as an advocate for the zebrafish as an important model for development and disease research. Ongoing dialog with the zebrafish research community, most recently at the Sixth International Meeting on Zebrafish Development and Genetics in June 2004, suggested a continuing need for not only tools, but high priority resources as well. Therefore, this PA is a continuation of the program initiated by PAR-02-142. The objective is to continue to broaden the range, power, and utility of tools for biomedical and behavioral research using zebrafish, and to develop genetic and genomic resources of high priority to the zebrafish community. Methodology developed and data and mutants generated as a result of this PA are expected to be made widely available to the research community as described by NIH Grants Policy.