April 14, 2003
Monday - 12:00pm in Swain West 238
Speaker: Maya Paczuski (Imperial College)
Title: Self-organized boolean networks

Abstract:
Networks of elements under mutual regulation or influence are seen in many biological and social systems ranging from genetic regulatory systems to economics. Already in the 1960's, Kauffman argued that Boolean networks could describe a variety of empirical features of the regulatory processes taking place during ontogeny, particularly cell differentiation. Natural selection tunes regulatory networks close to an "edge of chaos", characterized by several scaling laws, where they exhibit both homeostatic stability and evolutionary adaptability. In this talk, I present an explicit dynamical mechanism for self-organization in boolean networks based on Darwinian selection of the least fit element. This weeding out mechanism drives the networks to a state poised between the chaotic regime with no well-defined cell types, and a completely frozen regime with no complex dynamics. In the self-organized state, there are both finite attractors, corresponding to different cell types, and complex dynamics, required for cell differentiation.

(M. Paczuski, K. Bassler, and A. Corral, Phys. Rev. Lett. 84, 3185 (2000).)