Successful breeding of the laboratory mouse (Mus musculus) is critical to the establishment and maintenance of a productive animal colony. Additionally, mouse embryos are frequently studied to answer questions about developmental processes. A wide variety of genetic tools now exist for regulating gene expression during mouse embryonic and postnatal development, which can help scientists to understand more about heritable diseases affecting human development.

This video provides an introduction to the reproduction and development of mice. In addition to clarifying the terminology used to describe developmental progression, the presentation reviews key stages of the mouse life cycle. First, major development events that take place in utero are described, with special attention given to the unique layout of early rodent embryos. Next, husbandry protocols are provided for postnatal mice, or pups, including the process of weaning, or removal of pups from their mother's cage. Since males and females must be separated at this stage to prevent unscheduled mating, the demonstration also reveals how to determine mouse sex. Subsequently, instructions are given for carrying out controlled mouse breeding, including screening for the copulatory plug, which is useful for precisely timed embryonic development. Finally, the video highlights strategies used to investigate the complex processes that govern mouse development, including the generation of genetically altered “knockout” mice.