Figure 4.

High-fitness mitotypes provide competitive advantage. Overnight cultures of yeast strains containing the YJM975 nuclear genotype and YJM975 (blue) or Y12 (red) mitotypes were mixed and competitively grown on solid respiratory media (YPEG_R). The proportion of cells containing each mitotype was determined before (t = 0) and after competition on YPEG media for 2 days by counting numbers of large (Y12) and small (YJM975) colonies that formed on YPEG media at 37°. Proportions shown are based on total numbers of colonies counted before (n = 223) and after competition at 30° (n = 391) and 37° (n = 205). Significance codes following Bonferroni correction: ns (not significant) P > 0.05, * P < 0.05, ** P < 0.005, and *** P < 5 × 10⁻⁶.