  In cellular reprogramming, almost all epigenetic memories of differentiated
cells are erased by the overexpression of few genes, regaining pluripotency,
potentiality for differentiation. Considering the interplay between oscillatory
gene expression and slower epigenetic modifications, such reprogramming is
perceived as an unintuitive, global attraction to the unstable manifold of a
saddle, which represents pluripotency. The universality of this scheme is
confirmed by the repressilator model, and by gene regulatory networks randomly
generated and those extracted from embryonic stem cells.
