Physical mapping and RFLP analysis of mtDNAs from the ascosporogenous yeasts: Saccharomyces exiguus, S. kluyveri and Hansenula wingei.

Mitochondrial DNAs from the ascosporogenous yeasts S. exiguus, S. kluyveri and H. wingei were prepared by a new rapid method without CsCl isopycnic centrifugation. The mtDNA RFLPs were identified and clearly distinguished each species from the other. The physical maps were constructed by single and double digestion with nine restriction endonucleases. The location of rRNA genes was assigned to the maps by Southern hybridization with synthetic consensus probes. The genome sizes of these mtDNAs were estimated to be 45 kb for S. exiguus, 54 kb for S. kluyveri and 27 kb for H. wingei. The mtDNA RFLP analysis indicates a phylogenetic relationship among these yeasts. This indicates that S. cerevisiae is closer to H. wingei than S. kluyveri. However, the derived phylogenetic tree is completely consistent with that which was previously constructed on amino acid replacement in mating pheromones and electrophoretic karyotypes (Yoshida et al., 1989).