S73: Systems level characterization of adaptive evolution in yeast

Despite the progress in the rational design strategies via metabolic engineering, strain development in the biotech industry predominantly occurs by lab-based evolution and selection. While superior candidate strains are used for subsequent testing, this process has not resulted in advancing our understanding of microbiology. Tools from systems biology have provided opportunities to for multi-dimensional analysis of the system of interest. In this project, we made a systems-level enquiry into the intracellular changes in yeast during its evolution on galactose with the goal of relating these changes to the acquired phenotypic properties. We evolved Saccharomyces cerevisiae in three lineages on galactose for faster growth. After about 400 generations of evolution, the specific growth rate increased in the three lineages, but resulted in different fermentative capacities. Using a combination of genome sequencing, transcriptomics and metabolite profiling, we seek to relate the genotypic changes to the phenotype. We will present an integrated analysis of other changes that are common to the three lineages and those that are specific to each lineage. The implications of the result on metabolic network analysis and impact of systems biology on characterization of evolved mutants and evolution study are discussed.