Sensitivity of S. cerevisiae cells to atovaquone exposure. The name and position of the strains tested are shown above the plates. ΔYOR1, ΔYCF1, ΔPDR3, ΔSNQ2, ΔPDR15, ΔPDR10, ΔPDR1, ΔPDR5, and ΔPDR11 are strains carrying single deletions of genes of the ABC transporter family; AD1-9 carries deletions of all these genes (left-hand panels). The right-hand panels show the growth of AD1-9 and the seven strains derived from AD1-9 which carry cytochrome b mutations. WT, wild type.