S40: Personalized genomics for brewing yeasts

The lager beer yeast Saccharomyces pastorianus is an interspecific hybrid, formed by the mating of S. cerevisiae and S. eubayanus yeasts; efforts to understand its complex genome, searching for both biological and brewing-related insights, have been underway since its hybrid nature was first discovered.  Using microarray-based Comparative Genomic Hybridization (aCGH), we previously showed that there may have been two independent origins of S. pastorianus strains, with each independent group defined by characteristic genome rearrangements, copy number variations, ploidy differences, and DNA sequence polymorphisms.  We determined that the most likely S. cerevisiae ancestral parent for each of the independent S. pastorianus groups was an ale yeast, with different, but closely-related, ale strains contributing to each group’s parentage.  In the current era of increasing accessibility (and decreasing prices) of high throughput DNA sequencing, it is now feasible to determine the whole genome sequences for each of the different yeast strains used in a given brewery.  The knowledge gained from these sequences, especially the identification of uniquely absent and/or uniquely present DNA regions in a given strain, can be utilized--even among very closely-related yeasts--to design primers for PCR-type analyses that allow unique strain identification and/or detection of contamination of a culture with any of the other resident yeast strains.  Similar analyses can undoubtedly be performed for yeast strain identification and contamination detection in any given industrial setting.