Zebrafish Development and Genetics - PROJECT SUMMARY This proposal, entitled Zebrafish Development and Genetics , requests support for an intensive two-week laboratory and lecture course held at the Marine Biological Laboratory (MBL) for advanced graduate students, postdoctoral fellows and independent investigators that focuses on the development and genetics of zebrafish, with special emphasis on the mechanistic basis of embryogenesis, organogenesis, and regeneration. In its 24th year, the MBL Zebrafish course is still the only one of its kind worldwide, covering time-proven and newly- developed technologies and their applications in zebrafish. Mornings and afternoons are devoted primarily to laboratory exercises punctuated with interactive workshops, while the evenings are typically spent on data evaluation, lectures by leading figures in the international zebrafish community, and discussions. During the first week of the course, students learn concepts and techniques that are crucial for most zebrafish laboratories working on embryos and larvae: staging and anatomy, microscopy, microinjection, in situ hybridization, immunohistochemistry and imaging. Emphasis is placed on best practices for achieving rigor and reproducibility using each approach. The first week also focuses on genetics, with workshops covering genome editing and web-based genomics resources. The second week focuses on development and function of various organ systems, including concepts and techniques related to specific developmental disorders and tissue regeneration. Having been introduced to embryonic, larval, and adult anatomy in week one, students then learn techniques for labeling, ablating and transplanting cells to assess cell fate, morphogenesis and regeneration. Emphasis is placed on high-resolution live imaging of fluorescent transgenic reporters, including quantitative approaches for tracking cell movement and cell shape changes. Additionally, the course teaches techniques for studying larval visual and locomotor behaviors, including the genes and neural circuits involved. Throughout the two-week course, laboratory sessions are interspersed with workshop-style roundtable discussions that cover practical aspects of zebrafish research (e.g. when to select fish as a model organism, best practices in fish husbandry) and discuss the latest developments in the field (e.g. strategies for disease modeling, single cell -omics ). Finally, each of the course faculty presents a lecture centered on their current research. These highly interactive seminars are considered to be a highlight of the course, as they frequently nucleate engaging discussions about outstanding biological questions that extend well into the evening. The MBL Zebrafish course has received rave reviews from previous trainees. It strives both for scientific excellence as well as to train a diverse and inclusive group of scientists joining the zebrafish community. It is carefully crafted to provide newcomers to the zebrafish field with training in essential techniques and cutting- edge strategies used in this system. In addition, by facilitating interactions with leading figures in zebrafish research, the course creates a fruitful ground for its students to network and develop enduring collaborations.