Detalle de: Recombination-driven evolution of ADH2 confers a competitive advantage to domesticated wine yeasts

Adaptation, the process by which traits enhance an organism’s fitness, has traditionally been viewed through the lens of gradual allele frequency changes. However, contemporary genomic insights suggest that evolutionary novelty often emerges from large-effect mutations and de novo genic rearrangements. In the context of anthropogenic environments, Saccharomyces cerevisiae has undergone intense selection during industrial fermentation, leading to the emergence of specialised 'wine strains' uniquely adapted to grape must. Here, we identify a distinct ADH2 allele specific to these lineages, arising from an ancestral recombination event between ADH1 and ADH2. While such recombination is detectable across diverse yeast clades, only wine-associated strains possess a conserved variant distinguished by three specific amino acid substitutions (H21Y, P31A, and T59V). Biochemical assays revealed that this variant exhibit reduced ethanol affinity and increased acetaldehyde affinity, a kinetic shift that facilitates accelerated ethanol production during the early stages of fermentation. Allele-swap experiments demonstrate that this recombinant variant drives rapid ethanol accumulation, thereby conferring a critical competitive advantage in high-sugar environments. Our findings illustrate how structural genomic variation, refined by specific point mutations, provides a mechanism for rapid niche adaptation, highlighting the profound impact of human-driven selective pressures on the molecular evolution and domestication of microbial communities.