Poisson distribution of target molecules at very low concentrations.

<p>Poisson distribution dictates that aliquots taken at low target concentrations will contain a range of target quantities, such that a specific quantity of target (X-axis, N) is produced at a frequency (Y-axis, percent of all aliquots) that is dependent on target concentration (Z-axis, N_av). Zero molecule aliquots (0 N) are designated by yellow bars, which in the absence of non-specific amplification will fail to produce an amplification profile.