Embryonic stem cells detached from inner cell mass(ICM),can maintain self-renewal undifferentiation status and differentiate into almost every type of cells.

• 胚胎干细胞是从早期胚胎内细胞团中分离得到的,可以长久维持对称性自我更新的未分化状态,也可以分化成机体几乎所有类型的细胞。