Comparison of natural yeast hybrids

Analysis of genomic variation in several Saccharomyces cerevisiae x S. kudriavzevii natural hybrids S. cerevisiae and S. kudriavzevii yeasts have been described among wine strains. These strains exhibit enological properties of interest for the wine industry. A preliminary characterization of these hybrids showed a trend to reduce the S. kudriavzevii fraction of the hybrid genome. As a first approach to understand the mechanisms involved in the genome changes occurred after hybridization that may account for differences in their enological properties, we characterized the genomic constitution of several wine S. cerevisiae x S. kudriavzevii strains by using a combined approach based on the RFLP analysis of gene regions, comparative genome hybridizations with S. cerevisiae DNA arrays, ploidy analysis and gene dose determination by quantitative real-time PCR. Genomic DNA hybridizations of w27, w46, SPG1691 and 441 hybrids were compared against the laboratory strain FY1679. Hybridizations were performed by triplicate in order to obtain the final CGH ratio.