Abstract:
Understanding genetic mechanisms that enable populations to adapt to novel environments is required to predict their evolutionary fate. To study these mechanisms we developed an experimental system using budding yeast Saccharomyces cerevisiae, where starvation serves as a proxy to a variety of stressful environmental conditions. We found that cell populations starved for long periods of time accumulate genomic rearrangements but display only a modest increase in point mutations. The survivors with restructured genomes were more resilient to starvation than their common ancestor, and some isolates exhibited reproductive isolation. Because both resilience to starvation and reproductive isolation were strongly associated with genomic restructuring, severe environmental stress may actually increase the rate of incipient speciation and evolution. Here, we will explore the dynamics of starvation-associated genomic restructuring, analyze the underlying population distribution and dynamics of genomic restructuring events across subpopulations, and report on unanticipated effects of starvation such as clustering/multicellular phenotype in starved populations.