Relative retention of mitochondrial markers in petite mutants: mitochondrially determined differences betweenRHO(+) strains

Abstract

SUMMARY: The relative frequency of retention of two mitochondrial loci, determining resistance to oligomycin (oli1) and erythromycin (ery1), has been analysed in petite (rho(−)) mutants derived from a number of unrelated strains ofSaccharomyces cerevisiae. The frequency of retention of one marker relative to the other in spontaneous petites showed marked variation dependent on the strain of origin. The differences between strains in this characteristic were shown to be mitochondrially determined. Further, for individual strains, the relative retention of the markers in petites derived after UV-irradiation varied considerably in several cases from that observed with spontaneous petites. The observations on relative marker retention and the varied effects of UV-irradiation are discussed in terms of possible structural differences in the mitochondrial genomes of the various strains.