The main goal of this project is to perform a comparative genomics study of genes encoding mammalian seminal fluid proteins. Proteins found in seminal fluid accompanying sperm show drastic effects on reproduction, such as manipulating female behavior. Even in mammals they participate in competition between sperm of different males, and serve to protect sperm from infection by pathogens. These types of roles require the proteins to constantly adapt to stay ahead of the competition. Such adaptive pressures on proteins leave characteristic signatures in the DNA sequences that encode them. We will use these signatures to identify adaptive evolution in rodent seminal proteins and compare patterns to those previously found in primates. Additionally, we will investigate the origin of seminal fluid genes in primates and rodents - are the same orthologous genes used between these groups? ? ? This proposal is aimed at the identification of genes encoding mouse seminal fluid proteins and the comparative genomics of mouse and human seminal fluid genes. Seminal fluid is likely to regulate many aspects of fertilization. Factors in the seminal fluid could be important for sperm maturation, modulating female immune response to protect sperm, sperm storage, and even sperm - egg interaction. Thus, it is important to characterize the components of mammalian seminal fluid. Evolutionary dynamics of these genes could also be important for cancer research. It is important to explore the possibility that adaptive evolution of seminal fluid factors contributes to disease through pleiotropic effects. Adaptation in prostate-expressed genes may benefit primates during their reproductive lifespan, but could lead to damaging side effects in later life. ? ? ?