| Abstract: | Viable meiotic segregants were isolated from a bottom fermenting brewing yeast transformed by IME1 using a high copy number plasmid. These transformants sporulated under sporulation conditions and viable meiotic segregants were obtained from the spore asci. Flow cytometry showed that the meiotic segregants had a lower DNA content per cell than the parental strains, indicating meiosis had proceeded normally. Chromosomal observation by pulsed‐field gel electrophoresis and array comparative genomic hybridization (array‐CGH) showed that meiotic segregants, like the parent strains, contained two types of chromosome: the S. cerevisiae type and the S. bayanus type. In certain meiotic segregants, some chromosomes were missing, and the chromosome copy number changed. Isolation of meiotic segregants resulted in a ploidy reduction, which can be applied in the breeding of yeast strains. |
