Answer:
Murine, primate and human embryonic stem cells (ESCs) exhibit a very unusual cell cycle structure, characterized by a short G1 phase and a high proportion of cells in the S-phase.
Explanation:
Normally, embryonic stem (ES) cells proliferate quickly during differentiation and do not differentiate simply by cell cycle slowing. In this paper, it is shown that the role of the cell cycle in terminal stages of differentiation can be adapted for and extended into ES cells.
