Age-specific genomic and transcriptomic variation reveals limited evidence for cis-regulatory interactions modulating aging in Saccharomyces cerevisiae.

Abstract

The budding yeast Saccharomyces cerevisiae is a well-established model for studying the genetic basis of complex traits, and it is a powerful system for investigating mechanisms of aging. Here, we examine the genomic and transcriptomic factors contributing to increased replicative age in recombinant yeast populations harboring standing genetic variation. Using Fluorescence-Activated Cell Sorting (FACS), we isolated young and aged cohort pairs across twelve biological replicates and sequenced their progeny to assess patterns of differentiation at the nucleotide and transcription levels. Most differentiated alleles were located in coding regions, including significant variants within 132 unique genes. Transcriptomic analysis revealed 60 differentially expressed genes in aged populations, including 18 genes with increased expression in aged cohorts, and 42 genes with decreased expression. Although only two genes (RFA3 and WSC4) were implicated in both genomic and transcriptomic analyses, functional overlap associated with protein homeostasis, DNA repair, and cell cycle regulation was evident across datasets. Notably, we found no strong evidence that differentially expressed genes were more likely to occur in close proximity to significant gene variants. This suggests that late-life survival is not predominantly governed by background-independent local cis-regulatory interactions. These findings are consistent with a polygenic architecture in which distinct genotypes may promote longevity through diverse regulatory mechanisms.