Open AccessDouble sterility barrier between S accharomyces species and its breakdown in allopolyploid hybrids by chromosome loss
Author(s) -
Pfliegler Walter P.,
Antunovics Zsuzsa,
Sipiczki Matthias
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2012.00820.x
Subject(s) - biology , sterility , ploidy , genetics , saccharomyces , hybrid , locus (genetics) , meiosis , mating type , saccharomyces cerevisiae , zygote , gene , botany , embryogenesis
The analysis of 57 synthetic interspecies hybrids revealed that S accharomyces cerevisiae and S accharomyces uvarum ( S accharomyces bayanus var. uvarum ) are isolated by a double sterility barrier: by hybrid sterility (hybrid cells cannot produce viable spores) operating in allodiploids and by F 1 sterility ( F 1 cells cannot produce viable spores) operating in allopolyploids. F 1‐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 F 1 segregants, the cells can conjugate with each other like haploids and form zygotes capable of performing meiotic divisions producing viable and fertile F 2 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 S accharomyces genus.