The Use of Mitochondrial Mutants in the Isolation of Hybrids Involving Industrial Yeast Strains

Methods for the isolation of hybrids in which one or both of the parental strains are industrial yeasts, using mitochondrial mutations as markers for the selection and isolation of the hybrids, are described. The systems used included crosses of industrial strains with auxotrophic laboratory strains which also carried a mitochondrial antibiotic resistance mutation, crosses using an auxotrophic laboratory strain and a petite mutant of an industrial strain carrying a rescuable antibiotic resistance mutation, and crosses using a petite mutant of an industrial strain, carrying a rescuable mitochondrial mutation for antibiotic resistance and a respiratory-competent industrial strain which carried some other marker.