Somatic hybridization in Saccharomyces cerevisiae: analysis of products of protoplast fusion [yeast, spheroplasts, polyethylene glycol, karyogamy, tetrad analysis]
1979
Christensen, B.E.
Yeast strains of identical mating type were converted into protolasts with snail gut enzymes. Fusion induced with polyethylene glycol gave products in which nutritional requirements had complemented each other. The somatic hybrids were invariably maters and non-sporulators. When the strains differed in non-mendelian markers not used in the selection, these markers were found in the expected parental and recombinant combinations in the fusion products. Fusion products of two strains of mating type alpha were mated with fusion products of two strains of mating type a. Two cycles of sporulation and tetrad analysis of the presumed tetraploid gave a regular distribution of all markers showing that the somatic hybrids were indeed diploids homozygous for mating type. A single exception to the expected segregation was found not to be due to an abnormal chromosome number but is attributed to a gene conversion or a mitotic crossing over.
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