title: Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts.
abstract: Beer is one of the oldest alcoholic beverages and is produced by the fermentation of sugars derived from starches present in cereal grains. Contrary to lager beers, made by bottom-fermenting strains of Saccharomyces pastorianus, a hybrid yeast, ale beers are closer to the ancient beer type and are fermented by S. cerevisiae, a top-fermenting yeast. Here, we use population genomics to investigate (1) the closest relatives of top-fermenting beer yeasts; (2) whether top-fermenting yeasts represent an independent domestication event separate from those already described; (3) whether single or multiple beer yeast domestication events can be inferred; and (4) whether top-fermenting yeasts represent non-recombinant or recombinant lineages. Our results revealed that top-fermenting beer yeasts are polyphyletic, with a main clade composed of at least three subgroups, dominantly represented by the German, British, and wheat beer strains. Other beer strains were phylogenetically close to sake, wine, or bread yeasts. We detected genetic signatures of beer yeast domestication by investigating genes previously linked to brewing and using genome-wide scans. We propose that the emergence of the main clade of beer yeasts is related with a domestication event distinct from the previously known cases of wine and sake yeast domestication. The nucleotide diversity of the main beer clade more than doubled that of wine yeasts, which might be a consequence of fundamental differences in the modes of beer and wine yeast domestication. The higher diversity of beer strains could be due to the more intense and different selection regimes associated to brewing.
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Gonçalves
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Pontes
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Almeida
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Barbosa
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Serra
authors.affiliation: Laboratorio de Microbiología Aplicada, Biotecnología y Bioinformática, Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales (IPATEC), CONICET-UNComahue, 8400 Bariloche, Argentina.
authors.forename: Diego
authors.initials: D
authors.lastname: Libkind
authors.affiliation: Research Center Weihenstephan for Brewing and Food Quality, TU München, 85354 Freising, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Hutzler
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Gonçalves
authors.affiliation: UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. Electronic address: jss@fct.unl.pt.
authors.forename: José Paulo
authors.initials: JP
authors.lastname: Sampaio
mesh_terms: D001515:Beer; D000071278:Domestication; D005285:Fermentation; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000145:classification* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D014920:Wine
chemical_list: D029701:Saccharomyces cerevisiae Proteins
keywords: Saccharomyces cerevisiae; beer; comparative genomics; domestication signatures; microbe domestication; phenolic off flavor (POF); top-fermenting ale beer; wheat beer; yeast population genomics