Canalization in the critical states of highly connected networks of competing Boolean nodes

Canalization is a classic concept in developmental biology that is thought to be an important feature of evolving systems. In a Boolean network, it is a form of network robustness in which a subset of the input signals controls the behavior of a node regardless of the remaining input. It has been shown that Boolean networks can become canalized if they evolve through a frustrated competition between nodes. This was demonstrated for large networks in which each node had K=3 inputs. Those networks evolve to a critical steady state at the border of two phases of dynamical behavior. Moreover, the evolution of these networks was shown to be associated with the symmetry of the evolutionary dynamics. We extend these results to the more highly connected K>3 cases and show that similar canalized critical steady states emerge with the same associated dynamical symmetry, but only if the evolutionary dynamics is biased toward homogeneous Boolean functions.