Continuation of a Genetics Training Program is proposed at the University of Colorado, Boulder. Support is requested for 18 predoctoral positions, within a program that includes over 100 graduate students and 107 postdoctoral trainees in two departments. The interdisciplinary training faculty of 35 includes 25 members of the Department of Molecular, Cellular, and Developmental Biology (MCDB), 6 members of the Biochemistry Program in the Department of Chemistry and Biochemistry (BCHM), and 4 geneticists from other departments. Faculty research interests are diverse, focusing on fundamental problems of life processes at the levels of molecules, cells, developing organisms, and evolution. Recent additions to the research space in MCDB and BCHM have augmented the training facilities available to the program, which include outstanding shared microscopy and image-processing facilities and a variety of support services. Trainees are admitted from a strong national pool of over 100 applicants annually, most with excellent undergraduate preparation including research experience. Following an intensive introductory course and three research rotations during the first year, students choose a faculty mentor and accomplish the remainder of their training primarily through original research in a stimulating and demanding intellectual environment, which includes advanced course offerings as well as active seminar programs and a biennial student-sponsored symposium. Most students complete the program in 5 to 6 years and go on to postdoctoral training and careers in academia, biomedical research institutions, or biotechnology industry.