Application of Chromosome Fingerprinting to the Differentiation of Brewing Yeasts

Chromosome fingerprinting was used to differentiate among a number of lager yeasts that were indistinguishable when examined by DNA restriction pattern analysis. Electrophoresis conditions were varied empirically to obtain optimal resolution of chromosomes in various size ranges. Details of the practical application of the technique are described with the investigation of putative mutants of a brewing yeast. This application illustrated the problems in differentiating brewery yeast and contaminants with the use of classical microbiological procedures. The technique also was used to verify the integrity of isolates of another brewing yeast obtained from outside sources.