Probing noise in gene expression and protein production

We derive exact solutions of simplified models for the temporal evolution of the protein concentration within a cell population arbitrarily far from the stationary state. We show that monitoring the dynamics can assist in modeling and understanding the nature of the noise in gene expression. We analyze the dispersion of the process, i.e., the ratio of the variance to the mean at arbitrary time, and introduce a measure, the fractional protein distribution, which can be used to probe the phase of transcription of DNA into mRNA.