Paper ID: 124
1 The Australian Wine Research Institute (Australia)
2 Macquarie University (Australia)
The International Synthetic Yeast Genome Project (Sc2.0) is currently in the process of re-engineering and synthesizing the genome of the yeast Saccharomyces cerevisiae. Due to its long-standing use as a key model system, combined with its complete and well-characterized genome sequence, the Sc2.0 consortium is focusing its efforts on the S228c laboratory strain of S. cerevisiae, which has ~6000 genes spread over 16 chromosomes.
However, there are hundreds of different strains of S. cerevisiae and many have distinctive phenotypes that provide an advantage to a specific environmental niche or industry (fermenting wine, leavening bread or brewing beer). These phenotypic differences are the direct result of specific genetic variation between strains and this can range from single nucleotide polymorphisms to the presence of strain-specific genes or gene clusters. The presence or absence of these genes between strains can have striking phenotypic consequences, including providing strains with the ability to synthesize vitamins or to endure specific types of stress or inhibitory compounds.
To provide greater insight into the role of these strain-specific genes, we have identified over 200 kb of non-repetitive DNA, encoding 75 ORFs, which exist across the breadth of strain-specific ORF diversity of the S. cerevisiae pan-genome, but which are absent from the laboratory strain used for Sc2.0. These sequences have been synthesized and assembled, using Sc2.0 principles (watermarking, loxP sites), into a circular, centromeric neo-chromosome. This pan-genome neo-chromosome is now being analyzed to determine the phenotypes that it can impart in the laboratory strain background, while also providing a resource for introducing additional variation into the Sc2.0 genome through processes such as SCRaMbLE.