Analysis and generic properties of gene regulatory networks with graded response functions

We show that for steep sigmoid functions the flow may be highly sensitive to the relative steepnesses of the sigmoids. This has important consequences when stochastic effects are taken into account. Also, it implies that the observation by Glass and Kauffman in 1973 that the qualitative features of the solution do not change provided the underlying “logical” structure of the model is preserved, is not a generic property of gene regulatory models.