Beneficial Reversals Of Dominance: variable dominance and adaptation to new environments through an integrative approach – BROD

Genetic dominance significantly influences how mutations are seen by natural selection and affects evolutionary outcomes. Traditionally viewed as a fixed parameter in population genetics models, recent findings suggest that dominance can vary across lineages, sexes, and environmental conditions. This variation raises critical questions about its role in maintaining genetic diversity and facilitating adaptation to new environments. The goals of this proposal are to: 1) Assess the prevalence of Beneficial Reversals of Dominance (BRD) during adaptation to new environments; 2) Explore the regulatory mechanisms behind gene expression changes associated with BRD. 3) Investigate the conditions necessary for the evolution of genetic modifiers; and 4) Detect BRD-associated genes from nucleotide diversity patterns in natural populations of Saccharomyces cerevisiae. This project will integrate empirical genomic and transcriptomic data with theoretical models to explore BRD in S. cerevisiae, a domesticated species of ecological and agricultural significance. We will conduct phenotypic assays across 49 stressful conditions using a diallel panel of hybrids from diverse ecotypes. RNA sequencing will help identify allele-specific expression patterns that elucidate the molecular mechanisms driving BRD. Individual-based simulations will model the effects of genetic modifiers on adaptation, while machine learning techniques will be employed to detect BRD-driven balancing selection from genomic data. That said, we will provide a more comprehensive understanding of the prevalence and the molecular and evolutionary mechanisms underlying BRD which is critical to elucidate the mechanisms of adaptation and the maintenance of genetic variation under changing environments.