Spheroplast Fusion of Brewer's Yeast Strains

Spheroplasts of brewing polyploid yeast strains have been successfully fused with spheroplasts of haploid yeast strains. After regeneration of the cell wall, stable fusion recombinants were isolated. Genetic analysis of these recombinants revealed that they contained the genotype of both parents, sporulated well with each ascus containing four spores and were indeed diploid. Spheroplast fusion thus affords a means to genetically analyse brewing yeast strains, such an analysis having been difficult if not impossible by conventional hybridization techniques.