Centrosome amplification and proliferation of HeLa and CHO cells after cleavage failure. (A) Proliferative capacity of binuclear HeLa cells (yellow bars) and same preparation control cells (green bars). Black portions of bars indicate the percentage of the cells that die during or just after that mitosis. (B) Proliferative capacity of binuclear CHO cells (yellow bars) and same-preparation control cells (green bars). The darker portions of the yellow bars denote the percentage of cells that fail cleavage at each mitosis. (A and B) One experiment is shown on multiple cells. (C) Centrosome amplification after repeated cleavage failure in CHO cell populations. The experimental protocol and display of the results are the same as those shown in Fig. 1 A. The percentages of binuclear cells after cytochalasin treatments are shown in blue. The percentages of centrosome amplification (more than four centrioles) are shown in bold with the number of cells counted shown above or below.