Guo, S. et al. Cell 156, 649–662 (2014).

Reprogramming of somatic cells to induced pluripotency is in most cases very inefficient. It is thought to be a stochastic process, with as-yet unknown factors influencing the emergence of rare cells in which the barriers for cell fate conversion are removed or much lowered. Guo et al. now identify in mouse cells a 'privileged' state for which reprogramming is fast, synchronous and efficient and that therefore does not have the hallmarks of a stochastic process at all. Working first with mouse granulocyte-monocyte progenitors, which are known to reprogram at high efficiency, but then extending their studies to other murine hematopoietic cell populations as well as mouse embryonic fibroblasts, the researchers identify a very fast cell-cycle duration as a prospective indicator of the privileged, reprogrammable state.