> The challenge is moving from Turing's admittedly simplified model to pinpointing the precise mechanisms serving in the activator and inhibitor roles. This is

> The challenge is moving from Turing's admittedly simplified model to pinpointing the precise mechanisms serving in the activator and inhibitor roles. This is especially challenging in biology, where scientists are keen to shed more light on the question of how a complex embryo can emerge from tissue that is completely homogenous. Maybe I'm just too deep into my Theory of Computation class right now, but this sounds a lot like a closure (or lack thereof) property in the set of "homogenous tissue", no?