Nature of left telomeric structure of chromosome VI in sake yeasts

It was previously revealed that NotI generates 9 and/or 16 kb fragments fro m chromosome VI of sake yeasts isolated over the past several decades, wher eas the enzyme does not cleave the same chromosome in any other strains of the genus Saccharomyces, including older sake yeast isolates. Here, the cha racteristics of the 9 kb fragment were investigated. When the fragment was cleaved into two segments with EcoRI, one of them hybridized with all chrom osomes of all the fermentative yeasts tested, suggesting that it is compris ed of telomeric sequences. The other selectively reacted with a few chromos omes of sake, wine and bakers' yeasts. The signal intensities indicated tha t all strains of Saccharomyces sensu stricto share sequences more or less h omologous to those contained in the fragment. On the other hand, occurrence of the NotI site appears to be a phylogenetically recent event.