Multiple hybridization events gave rise to lager yeasts, according to a genomic analysis of Saccharomyces eubayanus and S. cerevisiae appearing in Molecular Biology and Evolution this week.
"Lager yeasts did not just originate once," the University of Wisconsin-Madison's Chris Todd Hittinger says in a statement. "This unlikely marriage between two species, genetically as different from one another as humans and birds, happened at least twice. Although these hybrids were different from the start, they also changed in some predictable ways during their domestication."
As GenomeWeb reports, Hittinger and his colleagues assembled the S. eubayanus genome and compared it to S. eubayanus x S. cerevisiae hybrids used to make lagers. This, the Los Angeles Times notes, follows a long search for S. eubayanus — the researchers found strains of it in Patagonia, Wisconsin, and China, though not in Europe.
This new comparison, the researchers say, indicates that the two main lager yeast lineages were created through two different hybridization events. Both lineages were derived from genetically similar S. eubayanus strains, but those strains hybridized with more diverse S. cerevisiae strains to yield lager yeast.
Hittinger tells the LA Times that his labs is continuing its search for other S. eubayanus strains to study the biogeography of lager yeast, and it is also exploring how to apply this yeast work to develop biofuels.