title: Molecular evidence for the existence of natural hybrids in the genus Zygosaccharomyces.
abstract: 26S rDNA D1/D2 sequencing was used to characterise a number of food-associated Zygosaccharomyces rouxii strains held at the National Collection of Yeast Cultures. In the course of this study, four strains (NCYC 1682, NCYC 3042, NCYC 3060 and NCYC 3061) were identified which appeared, based on their D1/D2 sequences, to belong to a novel Zygosaccharomyces species. However, subsequent sequence analysis showed that NCYC 1682, NCYC 3060 and NCYC 3061 possess two highly divergent copies of the nuclear-encoded ADE2, HIS3 and SOD2 genes, indicating these three strains are in fact hybrids. NCYC 3042, however, does appear to represent a novel species which may be hypothesized to have crossed with Z. rouxii and given rise to hybrid strains. Additional approaches to define precise taxonomic status and mechanisms of hybrid genome formation amongst yeast species are discussed.
authors.affiliation: National Collection of Yeast Cultures (NCYC), Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom. steve.james@bbsrc.ac.uk
authors.forename: Stephen A
authors.initials: SA
authors.lastname: James
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Bond
authors.forename: Malcolm
authors.initials: M
authors.lastname: Stratford
authors.forename: Ian N
authors.initials: IN
authors.lastname: Roberts
mesh_terms: D002262:Carboxy-Lyases / Q000235:genetics; D005516:Food Microbiology; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D014644:Genetic Variation; D006836:Hydro-Lyases / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics; D020068:Zygosaccharomyces / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; C434279:SOD2 protein, Zygosaccharomyces rouxii; D017923:Sodium-Hydrogen Exchangers; D002262:Carboxy-Lyases; C022378:phosphoribosylaminoimidazole carboxylase; D006836:Hydro-Lyases; C021434:imidazoleglycerolphosphate dehydratase