A team of researchers has found that yeast strains used for brewing beer are much more diverse than yeast used for wine, bread, and sake. The findings provide new insights into the domestication and history of beer yeasts. The details are in a paper that was just published in the journal Current Biology.
Beer, one of the oldest alcoholic drinks, has been produced by humans for at least 6,000 years. The drink is created by fermenting cereal grains, such as wheat and barley, with special strains of yeast. The genomes of these domesticated yeast strains had never been sequenced.
Researchers from Portugal analyzed the genomic data of 90 yeast strains from all around the world. 28 of the strains were associated with brewing beer while the rest were used for other purposes, including the production of sake, wine, and bread.
The team found that beer yeast species were very diverse. One major clade contained three distinct subgroups that consisted of German, British, and wheat beer yeast strains. All of the beer yeasts were polyphyletic, meaning they were derived from multiple evolutionary ancestors. Wine and sake yeasts, on the other hand, were genetically similar. The results suggest that beer yeasts emerged in a separate domestication event from other yeasts, such as wine yeasts. This came as a surprise to the researchers, who assumed that wine yeasts would be just as diverse as beer yeasts.
The domestication of yeast was an important time in history and led to products such as beer, wine, sake, and bread. Until now, these yeasts had never been genetically analyzed. The study’s findings show that beer had an especially complicated past, consisting of multiple domestication events and genetically dissimilar strains. This surprising find is helping researchers better understand how and when humans first domesticated yeast and began producing alcoholic beverages such as beer.
Gonçalves et al. Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts. Current Biology (2016).