Presence of STA gene sequences in brewer's yeast genome

STA genes are responsible for producing extracellular glucoamylase enzymes in Saccharomyces cerevisiae var. diastaticus. These genes exist in three forms, which are located on three different chromosomes. The nucleotide sequences of the STA genes are highly homologous. A sporulation-specific glucoamylase gene called SGAl exists in every Saccharomyces cervisiae strain, this also having a partly homologous DNA sequence with the STA genes. In this study S. cerevisiae var. diastaticus and brewer's yeast strains were characterized by pulsed-field gel electrophoresis. In many cases chromosome length polymorphism (CLP) was found. The chromosomes were hybridized with a DNA probe which was homologous with STA genes and the SGAl gene. Presence of the SGAl gene was detected in each strain used. Four brewing yeasts were found to have homologous sequences with the STA3 gene on chromosome XIV despite the fact that theses strains were not able to produce extracellular glucoamylase enzyme.