The Jackson Laboratory (JAX) has been a leader in mammalian genetics research and education since its inception in 1929. JAX pioneered the development of genetic approaches toward understanding fundamental questions in mammalian development and the genetic underpinnings of human disease. JAX also has a long and illustrious track record of training postdoctoral-and more recently predoctoral-scholars to be productive researchers at the nexus of systems genetics, genomics and computational biology. To support JAX's dual mission of discovery and education, we continually strive to provide cutting-edge, unique and highly relevant training opportunities designed to prepare all JAX trainees for successful scientific careers. The NICHD T32-funded Training Program in Developmental Genetics (TPDG), funded since 1977, is integral to the postdoctoral training environment at JAX. This developmental genetics-focused program provides high-quality postdoctoral training to prepare its trainees for careers as independent investigators in universities, research institutions and the biomedical industry. Today, the program brings together 18 highly productive and well-funded faculty mentors at the JAX Mammalian Genetics campus in Bar Harbor, ME, who provide a uniquely interdisciplinary, integrated and comprehensive training environment. Research areas include mammalian embryonic development, congenital birth defects associated with neurological, sensory and metabolic disease, stem cell biology, reproduction, systems genetics and bioinformatics. The TPDG has supported ~70 postdoctoral trainees to date, 20 during the past 10 years. Previous trainees have been highly successful in moving on to careers in academia, government and industry, and in obtaining research funding. In this resubmission of the TPDG we seek to continue to provide two slots for postdoctoral fellows and request support for two predoctoral students. JAX participates in collaborative Ph.D. training programs with the Tufts School of Medicine and the University of Maine that have grown to critical mass. Specific criteria are used to admit both pre- and postdoctoral trainees into the TPDG. Required and elective curricula have been developed to enrich the training experience. Trainees will test hypotheses regarding the genetic underpinnings of development and disease, and will model new diagnostic and therapeutic modalities, using cutting-edge computational and mouse genetics resources uniquely available to them at JAX. Trainees will have access to focused and individualized career development opportunities, such as teaching and grant writing experiences, and will be integrated into seminars, workshops, and research interest groups. They will write external funding applications, present their findings at scientific meetings, and publish in peer-reviewed journals. Trainee evaluation will be rigorous and coupled with support for growth. The TPDG will thus provide exceptional research opportunities in a stimulating scientific training environment and enable trainees to launch successful independent careers in biomedical research.