Figure 2

Polyploidy variation between BALB/cJ and BALB/cByJ. (A) CM analysis. Within the mononuclear CM and binuclear CM subgroups, the percentages of nuclei of the indicated ploidy (2n, diploid; 4n, tetraploid; 8n, octoploid) are shown. The 2n (diploid) percentage of mononuclear CMs is shown in Fig. 1B and not repeated here. Data were calculated in this manner because a disproportionately greater number of mononuclear CM nuclei were evaluated relative to their frequency in the heart. Error bars represent standard deviation. (B) Hepatocyte analysis. Same evaluation as for CMs; the 2n (diploid) percentage of mononuclear hepatocytes is shown in Fig. 1D and not repeated here. (C) Distribution of different polyploid subtypes for both CMs and hepatocytes, multiplying the data from panels A and B with the percentage of mononuclear and binuclear cells shown in Fig. 1A,C. 1 × 4n and 2 × 2n cells are both tetraploid; 1 × 8n and 2 × 4n cells are both octoploid. A small number of 2 × 8n cells were observed; there were too few cells with other types of polyploidy to show on this chart. (D) Analysis of CM polyploidy levels in F1 mice derived from crosses of BALB/cJ and BALB/cByJ parents in both directions; same color scheme as in panel C.