Even high school biology students knew that once a mammalian cell had differentiated, and was programmed by nature to be bone or nerve or skin, it could be deprogrammed.

• 甚至学生物的高中学生都知道一旦哺乳动物的细胞发生分化,由自然安排成为骨骼或神经或皮肤后,它就不能够再恢复原态了。