DNA sequence polymorphisms in the genus saccharomyces III. Restriction endonuclease fragment patterns of chromosomal regions in brewing and other yeast strains

Abstract

30 bottom fermenting strains, 13 hybrid lager strains, 11 top fermenting strains. In addition, 24 other yeast species and strains have been analysed in this study. Four DNA regions have been monitored by restriction endonuclease fragment pattern polymorphisms. The regions analysed are:RDN1 (encoding cytosolic ribosomal RNA molecules) located on chromosome XII in S. cerevisiae,HIS4 (histidine 4) andLEU2 (leucine 2) both located on chromosome III and theTy elements which are distributed at different positions in the genome of S. cerevisiae. SevenTy fragment patterns have been detected in the bottom fermenting strains. Patterns I, II, IIa, IIb, and IIc are present in lager strains while pattern III and IV are found in S. carlsbergensis bottom fermenting strain No. I and in S. monacensis, respectively. Hybridization of theTy1 p14 probe from S. cerevisiae to OFAGE separated chromosomes from bottom fermenting strains show that at least fiveTy elements are present in the genomes of the lager strains, at least five in S. carlsbergensis bottom fermenting strain No. I and at least three in S. monacensis. From the restriction fragment patterns and the karyotypes of the bottom fermenting strains it is suggested that these strains are closely related and different from the S. bayanus, S. pastorianus, and S. uvarum group as well as from the S. cerevisiae strains. In spite of their differences inTy element patterns the large strains are so homogenous that most likely they all originate from a single strain which is related to S. carlsbergensis and S. monacensis type strains. In contrast to the bottom fermenting strains there is a large variability among the top fermenting strains, especially with regard to theLEU2 gene andTy elements. It seems that S. bayanus, S. inusitatus, S. pastorianus, S. validus, and S. uvarum are closely related, and none of the studied strains from these taxons contained DNA which hybridized to theTy1 probe from S. cerevisiae. This is a clear difference from the DNA of bottom fermenting strains which consistently hybridized strongly to theTy1 probe.