Summing up the noise in gene networks

Ransom fluctuations in genetic networks are inevitable as chemical reactions are probabilistic and many genes, RNAs and proteins are present in low numbers per cell. Such 'noise' affects all life processes and has recently been measured using green protein (GFP). Two studies show that negative feedback suppresses noise, and three others identify the sources of in gene expression. Here I critically analyse these studies and present a simple equation that unifies and extends both the and biological perspectives.