Within 1 wk, the transferred cells proliferated and spread on the bottom of the well, and round proliferating cells formed colonies on top of the flat cell layer (Fig. 1, b and c).

• 约1周内，转移的细胞增殖展开于培养瓶底，圆形生殖细胞在一层扁平贴壁细胞上增殖形成克隆。