Stochastic models of gene expression with time delay

We will present an elementary introduction to stochastic models of gene expression. Master, Fokker-Planck, and Langevin equations will be discussed. We will review a simple model of protein production which can be completely solved, that is one can obtain analytical expressions for the expected value and the variance of the number of protein molecules (Thattai and Oudenaarden, PNAS, 8614-8619, 2001). Then we will discuss some simplified models with time delay and report on work in progress.