CHROMOSOMAL DELETION OR REARRANGEMENT IN CHIMERIC HYBRIDS OF SACCHAROMYCOPSIS-FIBULIGERA AND SACCHAROMYCES-DIASTATICUS OBTAINED BY CELL-FUSION

We isolated three hybrids of Saccharomycopsis fibuligera and Saccharom yces diastaticus, a species that secretes glucoamylase and that has be en reclassified recently as a strain of Saccharomyces cerevisiae, for yeast protoplast fusion, and characterized their chromosomes. When the chromosomes of the hybrids were analyzed by electrophoresis in a cont our-clamped homogeneous electric field, their migration patterns were similar to those of the parental strains but with slight differences b etween hybrids. Southern hybridization using the alpha-amylase and glu coamylase genes from S. fibuligera and S. diastaticus, respectively, a s probes showed that these genes were duplicated or deleted in the hyb rids. These results demonstrated that the hybrids contained chimeric c hromosomes as a result of recombination or rearrangement.