The biochemical processes leading to the synthesis of new proteins are random, as they
typically involve a small number of diffusing molecules. They lead to fluctuations in the
number of proteins in a single cell as a function of time and to cell-to-cell variability of protein
abundances. These in turn can lead to phenotypic heterogeneity in a population of
genetically identical cells. Phenotypic heterogeneity may have important consequences for
the development of multicellular organisms and the fitness of bacterial colonies, raising the�…