PROJECT SUMMARY The zebrafish is a widely used biomedical model organism and has been studied extensively at early stages. Current research efforts focus increasingly on later stages that are relevant to understanding fundamental as- pects of vertebrate development as well as human disease, birth defects and regenerative potential. This project will provide a resource to facilitate such studies by identifying molecular markers for specific cell types present at late stages, and mapping these markers and the cells they represent within the developing anatomy of the larval fish. Candidate markers and cell types will be identified using unbiased single cell transcriptomic approaches, and anatomical mapping will be accomplished using histological and imaging approaches, all of which are routine for this laboratory. These resources will enable efforts by the community of investigators us- ing zebrafish for biomedical research, and will provide opportunities to further exploit this system for under- standing and promoting human health.