FIGURE 2: Physical mapping of the mim3-1 suppressor.

The restriction map and position of 15s rRNA and COX1 (subunit I of cytochrome oxidase) genes are shown at the top. tsl: locus involved in tRNA maturation. The KG01 rho^– petite, carrying the mim3-1 mutation, was subjected to ethidium bromide mutagenesis and sub-cloned twice in the absence of the drug. A few hundred colonies were tested for suppression of the M3041 target mutation. + and – indicates suppression or its absence. Most of the sub-clones did not suppress any longer; 24 rho^– sub-clones were further analysed by restriction (only a few sites are shown) and blotting with a probe constituted by the KG01 mitochondrial DNA. The lengths and positions of tandem repeats retained in mtDNA of three discriminating petites are represented by thick bars indicating that the suppressor is located in the 15s rRNA gene.