To provide a nonhuman mammal, in which expression of Phgdh is lowered, which enables analysis of role of L-serine synthesis through Phgdh in formation of a central nervous system and retention of the function, at a later stage of cephalization, particularly in development after birth. 脳形成の後期、特に生後発達における中枢神経系の形成と機能の維持におけるPhgdhを介したL-セリン合成の役割を解析することを可能とするようなPhgdh発現低下型非ヒト哺乳動物を提供すること。 - 特許庁