Some Molecular Structures in the Genome of Lager Brewing Yeasts. M. Aigle, D. Erbs, and M. Moll, TEPRAL, Centre de Recherches et Développement, Branche Boissons BSN, 54250 Champigneulles, France. J. Am. Soc. Brew. Chem. 42:0001, 1984.

Some molecular features of the genome of two lager yeast strains were analyzed and found to be essentially tetraploid. In lager strains, cytoplasmic double-stranded RNA seems to be absent, or is present only in minute amounts. Although many lager strains are structurally identical, the mitochondrial DNA from these strains is different from that of other yeasts. The presence of the 2-µm DNA plasmid with standard structure was demonstrated in the strains tested. The DNA of lager strains contains repeated mobile elements related to the TY1 element described in Saccharomyces cerevisiae. The distribution of these elements in the genome was identical in the three production yeasts analyzed. Field applications of contaminant identification, stability tests, and genetic engineering are discussed.

Keywords: Double-stranded RNA, Lager yeasts, Mitochondrial DNA, Plasmid, Ploidy, TY element