A controversy concerning the structure of the mitochondrial genome of a yeast petite mutant: resolution by sequence analysis.

Sequence analysis was used to define the repeat unit that constitutes the mitochondrial genome of a petite (rho-) mutant of the yeast Saccharomyces cerevisiae. This mutant has retained and amplified in tandem a 2,547 bp segment encompassing the second exon of the oxi3 gene excised from wild-type mtDNA between two direct repeats of 11 nucleotides. The identity of the mtDNA segment retained in this petite has recently been questioned (van der Veen et al., 1988). The results presented here confirm the identity of this mtDNA segment to be that determined previously by restriction mapping (Carignani et al., 1983).