Double sterility barrier between Saccharomyces species and its breakdown in allopolyploid hybrids by chromosome loss

Walter P. Pfliegler, Zsuzsa Antunovics, Matthias Sipiczki

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The analysis of 57 synthetic interspecies hybrids revealed that Saccharomyces cerevisiae and Saccharomyces uvarum (Saccharomyces bayanus var. uvarum) are isolated by a double sterility barrier: by hybrid sterility (hybrid cells cannot produce viable spores) operating in allodiploids and by F1 sterility (F1 cells cannot produce viable spores) operating in allopolyploids. F1-sterility is caused by mating-type heterozygosity. It can be overcome by eliminating chromosome 2 of the S. uvarum subgenome that carries a MAT locus. The loss of this MAT gene abolishes the repression of mating activity. In cultures of the resulting fertile alloaneuploid F1 segregants, the cells can conjugate with each other like haploids and form zygotes capable of performing meiotic divisions producing viable and fertile F2 spores. To the best of our knowledge, this is the first report on breaking down interspecies hybrid sterility by chromosome loss in eukaryotic organisms. The filial generations are genetically unstable and can undergo additional changes mainly in the S. uvarum subgenome (directional changes). It is proposed that regaining fertility and subsequent preferential reduction in one of the subgenomes may account for the formation of chimerical ('natural hybrid') genomes found among wine and brewery strains and may also play roles in speciation of hybrid taxa in the Saccharomyces genus.

Original languageEnglish
Pages (from-to)703-718
Number of pages16
JournalFEMS Yeast Research
Volume12
Issue number6
DOIs
Publication statusPublished - Sep 1 2012

Keywords

  • Alloploid hybrid
  • Aneuploid
  • Genome segregation
  • Hybrid sterility
  • Saccharomyces cerevisiae
  • Saccharomyces uvarum

ASJC Scopus subject areas

  • Microbiology
  • Applied Microbiology and Biotechnology

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