Reproductive challenges in both human and livestock populations are of significant concern and are often a direct result of abnormal germ cell development. Aberrant germ cell differentiation significantly affects human fertility, is the leading cause of early pregnancy loss and results in birth defects such as Down’s syndrome and Klinefelter’s. Failed gametogenesis in livestock have significantly increased because of intense selection for commercial traits and decreased emphasis on reproductive success. Porcine sub-fertility and sterility, spontaneous fetal abortion, decrease litter size and abnormal offspring have all been linked to errors in germ cell development. Advances in studying germ cell development in humans and livestock have been hindered by a lack of a biologically relevant system to explore the mechanisms and causes of failed germ cell differentiation.
Recently we have demonstrated that embryonic and induced pluripotent stem cells are capable of differentiating into early germ cells that demonstrate germ cell morphology and immunoreactivity. Upon further differentiation these cells are able to enter into the germ cell defining event of meiosis where a diploid cell undergoes multiple cell divisions to give rise to haploid daughter cells. These cells represent an excellent tool to potentially study human germ cell development and signaling process in an easy to access in vitro system.