Orthogonal field alternation gelelectrophoresis (OFAGE) as a means for the analysis of somatic hybrids obtained by protoplast fusion of different Saccharomyces strains

Summary

PEG-induced fusion of two haploid Saccharomyces strains resulted in three morphologically different types of fusion products. In order to estimate the respective ploidy, one representative of each type — F ₁, F ₂ and F ₃ — was subjected to a measurement of the cellular DNA content and to a meiotic segregation analysis. The data obtained in these analyses suggested the strain F ₁ to be a haploid cybrid resulting from mere plasmogamy, whereas the hybrids F ₂ and F ₃ were likely to be the products of a successful nuclear fusion of two, respectively three, protoplasts of the parental strains. However, the complete genetic composition of the hybrids could only be revealed by OFAGE experiments, as the genetic data solely referred to a few chromosomes with marker genes. All the results of the OFAGE were in full accordance with the assumptions made in the conventional analysis, thus indicating the OFAGE to become a very promising means for the investigation of hybrids inaccessible to genetic analyses.