Fig. 2.

Modeling and determination of mtDNA loss rate in a growing cell population. a) Schematic of 2-state model of mtDNA loss in a growing population. G_wt is the growth constant of the wild-type cells, G_mut is the growth constant of the mutated ρ⁰ cells, r is the rate of mtDNA loss, P_wt is the population size of wild-type cells, P_mut is the population size of mutant ρ⁰ cells, t is time since the foundation of a population. b) Simulated population proportion of mtDNA mutants for a range of mutation rates and c) mutant growth rates. d) Time-resolved assay of mtDNA loss during mitochondrial protein stress. Cultures were kept in exponential growth phase for experiment duration by dilution with new media to avoid selecting for respiring cells. Circles represent measured petite frequencies in independent biological replicates, black circles indicate the population-weighted mean petite fraction from 8 biological replicates, error bars represent simple SEM of petite frequencies between each replicate (unweighted). e) Effect of mitochondrial modifiers on growth rate. Dots indicate rates from independent biological replicates. P values are calculated from a 2-tailed t-test.