FPi analysis. I. Theoretical outline of a new method to analyze time sequences of DNA histograms.

A new mathematical method is presented to analyze a time sequence of DNA distributions taken from perturbed cell populations. The method, called FPi analysis, consists of plotting the time variation of the fraction of cells in selected DNA contents 'windows' of the histogram. It is shown that kinetic information about the flow of cells through the cycle after the perturbation can be estimated from the FPi curves. An analysis of the method reveals that the method yields accurate results for the instrumental and cytochemical variations obtainable by present technology. The value of the method lies in the fact that the information needed can be obtained directly from the measured DNA distribution, thus bypassing the problems with other methods which estimate the fraction of cells in a given phase directly from a single histogram.