Dealing with noise: The challenge of buffering biological variability

Cells process information using bio-molecular circuits of interacting proteins and genes. A remarkable property of these circuits is their ability to function in highly variable biological environments: Biochemical processes are stochastic, environmental conditions fluctuate, and genetic polymorphisms are abundant. How is variability buffered to maintain a robust output? Can variability be exploited to allow computations not possible by deterministic dynamics? These questions lie at the heart of contemporary systems biology. We argue here that biological variability is fundamental for understanding principles underlying design and function of biological circuits. As concrete examples, we will discuss the buffering of variability during embryonic patterning, and the incorporation of variability in microbial responses to changing conditions.