This small research project focuses on the role of kinesin 8, Kif18A, which has an essential function in cell division and is broadly expressed, yet is uniquely required in the developing germ line. Mutations in mammalian Kif18A lead to germ cell depletion and ultimately infertility; however, infertility in mutant mice is not fully penetrat and is dependent on strain background. Therefore, there are genetic factors that ameliorate infertility in the context of Kif18A ablation. The unique role of Kif18a in germ line development has only recently been revealed and a mechanism for Kif18a function in the germ line has not been established. The overall goal of this small research project is to provide the basic biological data required to establish the mechanism by which Kif18A functions in germ line development and to create a genetic dataset for the discovery of the molecular pathways that modulate Kif18A dependent germ cell depletion. These data will contribute to the foundation of a larger research program focused on the specialization of germ cell division in the mammalian germ line, where maintenance of genome integrity is integral to gametogenesis and, critically, fertility.