title: Dominant Epistasis Between Two Quantitative Trait Loci Governing Sporulation Efficiency in YeastSaccharomyces cerevisiae.
abstract: Sporulation efficiency in the yeastSaccharomyces cerevisiaeis a well-established model for studying quantitative traits. A variety of genes and nucleotides causing different sporulation efficiencies in laboratory, as well as in wild strains, has already been extensively characterised (mainly by reciprocal hemizygosity analysis and nucleotide exchange methods). We applied a different strategy in order to analyze the variation in sporulation efficiency of laboratory yeast strains. Coupling classical quantitative genetic analysis with simulations of phenotypic distributions (a method we call phenotype modelling) enabled us to obtain a detailed picture of the quantitative trait loci (QTLs) relationships underlying the phenotypic variation of this trait. Using this approach, we were able to uncover a dominant epistatic inheritance of loci governing the phenotype. Moreover, a molecular analysis of known causative quantitative trait genes and nucleotides allowed for the detection of novel alleles, potentially responsible for the observed phenotypic variation. Based on the molecular data, we hypothesise that the observed dominant epistatic relationship could be caused by the interaction of multiple quantitative trait nucleotides distributed across a 60--kb QTL region located on chromosomeXIVand theRME1locus on chromosomeVII. Furthermore, we propose a model of molecular pathways which possibly underlie the phenotypic variation of this trait.
authors.affiliation: Laboratory for Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia.
authors.forename: Juraj
authors.initials: J
authors.lastname: Bergman
authors.affiliation: Laboratory for Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia; Institute for Research and Development of Sustainable Ecosystems, Faculty of Veterinary Medicine, Heinzelova 55, HR-10000 Zagreb, Croatia.
authors.forename: Petar T
authors.initials: PT
authors.lastname: Mitrikeski
authors.affiliation: Laboratory for Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia.
authors.forename: Krunoslav
authors.initials: K
authors.lastname: Brčić-Kostić
keywords: QTL analysis; budding yeast; phenotype simulation; sporulation inheritance; two-locus epistasis