Yeast domestication

Like plants and animals, microorganisms have also been domesticated since ancient times by humans. Domesticated yeasts are required for wine, beer and bread production, among many other food and beverage fermentations. In this review, the term 'domesticate' refers to an organism propagated by humans that is genetically and phenotypically distinct from its wild ancestors in ways that make it more useful to humans. A single species, Saccharomyces cerevisiae, is responsible for most yeast fermentations and separate lineages within this species carry out different fermentations. Besides alterations at the phenotypic level, domestication can lead to modifications in genome architecture and genome content. These changes, which can be viewed as domestication signatures, will be briefly reviewed here. We also present and discuss special cases of domestication like 'secondary domestication', the situation in which an already domesticated yeast endures a second round of artificial selection, and 'quasi-domestication', which corresponds to evidence of adaptation of a microorganism to an environment created by humans without a detectable positive impact on the characteristics of the fermented product. Finally, we analyze other cases of confirmed or possible domestication in other Saccharomyces species and among species outside of this genus, like Brettanomyces bruxellensis and Torulaspora delbrueckii.