Separation of anaphase cells from prometaphase cells by pairing score. (a) For the high MI experiment, the DAPI equality, parallelness, and symmetry were calculated for each cell that was both automatically classified as nonmetaphase post-NEBD and manually classified as prometaphase or metaphase, and each of these three measurements was plotted in a separate line histogram, color coded by stage (prometaphase, blue; anaphase, yellow). (b) The pairing score was computed for the same cell types in all three experiments and plotted on histograms color coded by stage as in (a). Both stages are on the same absolute frequency scale. In both (a) and (b), red vertical lines represent the pairing score threshold that separates the prometaphase class below from the anaphase class above. (c) The percentage of each manually determined cell cycle phase or mitotic stage (row headings) to fall into each automatic class (column headings) is shown. (d) A sample of cells from the high MI experiment is shown in order of pairing score. The pairing score of each cell is in the top left of each image, and its manual classification is in the bottom left. Pm, prometaphase; A, anaphase.