Genetic interaction network has a very limited impact on the evolutionary trajectories in continuous culture-grown populations of yeast

ABSTRACT: Background: The impact of genetic interaction networks on evolution is a fundamental issue. Previous studies have demonstrated that the topology of the network is determined by the properties of the cellular machinery. Functionally related genes frequently interact with one another, and they establish modules, e.g., modules of protein complexes and biochemical pathways. In this study, we experimentally tested the hypothesis that compensatory evolutionary modifications, such as mutations and transcriptional changes, occur frequently in genes from perturbed modules of genetically interacting genes. Results: Using haploid strains of Saccharomyces cerevisiae deletion mutants as a model, we investigated two modules lacking COG7 or NUP133, which are evolutionarily conserved genes with many compensatory interactions. We performed laboratory evolution experiments with strains bearing these mutations in two genetic backgrounds (with or without additional deletion of MSH2), subjecting them to continuous culture in a non-limiting minimal medium. Next, the evolved yeast populations were characterized through whole-genome sequencing and transcriptome analyses. No obvious compensatory changes resulting from inactivation of genes already included in modules were identified. The supposedly compensatory inactivation of genes in the evolved strains was only rarely observed to be in accordance with the established fitness effect of the genetic interaction network. In fact, a substantial majority of the gene inactivations were predicted to be neutral. Similarly, transcriptome changes during continuous culture mostly signified adaptation to growth conditions rather than compensation of the absence of COG7, NUP133 or MSH2 genes. Conclusions: Our findings demonstrate that the genetic interactions and modular structure of the network described in other studies have very limited effects on the evolutionary trajectory observed on the genomic and transcriptomic levels, following gene deletion of module elements and upon our experimental conditions. This observation indicates that the modular structure of the cellular machinery has no impact on compensatory evolution in the short term.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE167397 | GEO | 2021/02/25

REPOSITORIES: GEO