  We present a detailed kinetic model for the Polymerase Chain Reaction, and
model the probability of replication in terms of the physical parameters of the
problem. Applying the theory of branching processes, we show the existance of a
new phenomenon affecting the probability distribution function of the number of
replicants: for small number of initial molecules, the limiting behavior (with
increasing number of cycles) of the pdf is represented by a multi-modal
funtion.
