Our goal is to understand how the epigenetic network develops in the germline and how they are maintained thereafter. We also tried to correct or improve germline cells by epigenetic manipulation. We have conducted research for 5 years and obtained several important findings. This includes identification of sex determinant in the germline cells, derivation of pluripotent stem cells from spermatogonial stem cells, discovery of essential genes for completing spermatogenesis, analysis of the role of histone chaperone in implantation, and epigenome analysis of primordial germ cell-like cells during development from pluripotent stem cells. A total of X papers were published and Y% of them were conducted by collaboration by researchers in this research group. Four members were promoted to full professor.