They turn genes on and off in different patterns, so that a uniform clump of cells can give rise to bone, muscle and brain. 它们可在不同的模式下激活或关闭基因,从而使一群细胞统一地发育成骨骼、肌肉或脑。
For the tissue-growing experiment, the researchers focused on the clump of cells containing embryonic stem cells. 对于培养组织的实验来说,研究人员关注的是含有胚胎干细胞的这群细胞。
An inner clump of cells in the blastocyst goes on to form the embryo, while an outer layer goes on to make the placenta. 胚泡中的内层细胞随后形成胚胎,外层细胞则形成胎盘。