[Ploidy level in Streptomyces cerevisiae strain 15B-P4 strain].

Hybridization analysis of seven clones of Saccaromyces cerevisiae 15B-P4 strain, which were obtained from different cultures, was carried out. Yeast strains taken from the Peterhoff breeding stocks were kept in the laboratory of genetics at Biological Institute of Irkutsk University from 1970. Increase in the number of prototrophic segregants was shown to by the result of aneuploidy (2n + 1) in the hybrids under study. Aneuploidy was revealed for the chromosomes I, III, IX, XII. Disomic clones of 15B-P4 strain were unstable.