F. Böttcher

A set of genetic markers for the chromosomes of the imperfect yeast Arxula adeninivorans.

The nuclear genome of the anamorphic yeast Arxula adeninivorans was analysed by benomyl‐induced haploidization of parasexual hybrids marked with 32 auxotrophic mutations and pulsed field gel electrophoresis followed by DNA hybridization. Twenty‐seven genes have been arranged into four linkage groups by haploidization, 15 genes belong to group 1, six to group 2, and three each to groups 3 and 4. Five genes could be localized by DNA hybridization on three out of four separated chromosomes. The gene LYS2 of the largest linkage group 1 and the 25S rDNA were identified on the largest chromosome, the GAA and the TEF1 gene on chromosome 2, and the ILV1 gene of linkage group 4 on the smallest chromosome.

Genetic analysis of the yeastCandida maltosa by means of induced parasexual processes

The usefulness of hybridization by protoplast fusion and mitotic segregation for the genetic analysis of the imperfect fodder yeastCandida maltosa was tested. Mitotically stable fusion hybrids were obtained with frequencies between 10−6 and 10−7. Complementation tests were performed by protoplast fusion. Substances that are known to induce frequent mitotic segregation in other yeast species such as benomyl, p-fluorophenylalanine, and acriflavine were ineffective inC. maltosa. UV irradiation induced mitotic segregation in up to 10%. This agent induced mainly mitotic crossing over inC. maltosa. Our data enabled the construction of the linkage group I with the sequenceCEN-ade-26-pro-1.

A simple technique for random spore analysis of yeasts using nystatin

Abstract Random spore samples can be obtained by treatment of sporulating yeast cultures with the polyene antibiotic nystatin. Under suitable conditions, the spores are released from the asci and survive while the more sensitive vegetative cells are killed. Examples of the application of this simple and efficient one-step technique for genetic analysis in the yeasts Pichia guilliermondii and Saccharomyces cerevisiae are presented.