Mouse Embryo Services (MES) Core provides a broad, comprehensive range of services to investigators, including generation of gene editing mice, transgenic mice, ES cell microinjection into blastocysts to create germline competent chimera, cryopreservation and long-term storage of mouse sperm/embryos, recovery of mouse lines from cryopreserved germplasm, in vitro fertilization for mouse line rescue and re-derivation of pathogen free mouse strains.