分化为胚胎上皮细胞（epiblast，Epi）和原始内胚层（primitive endoderm，PrE）。这一过程中，胚胎保持了一段时间的多能性（plasticity），即在实验条件下 ...

After a sperm fertilizes an egg, the totipotent cell divides into a zygote. As division continues, some cells divide into the growing mass, distinguishing cells that form the embryo (epiblast) from ...