Bistability studies.

Each column represents a different feature of the model: (a) Epigenetic cooperativity with the Transcription factors; (b) the dimerization of the transcription factor NANOG; (c) the cooperative binding between OCT4 and SOX2; and (d) the observation of bistability. Each row represents a different model variation. The presence or absence of a feature in a model is marked respectively by a 1 or a 0. In the bistability column anrepresents no observed bistability, and a represents observed bistability; an arrow from one to the other represents a successful change in parameters resulting in bistability.