Researchers have solved the mystery of the cold-adapted yeast that blended with a distant cousin to make the lager-churning hybrid endured for almost 500 years.
A team led by University of Wisconsin-Madison Professor of Genetics Chris Hittinger confirms that Saccharomyces eubayanus, the wandering parent of hybrid lager yeast discovered in 2011, is indeed a native of Patagonia.
An analysis of the yeast's genetic sequence revealed its closest affinity to one of two highly diverse Patagonian populations, confirming it was the cold-loving microbe that, 500 years ago, found its way to the caves and monastery cellars of Bavaria where lager beer was first concocted.
Hittinger said that this yeast really is native to Patagonia and that they found two major populations that seem to be distinct. The trees they're associated with seem to provide everything they need.
Hittinger's colleague, Diego Libkind of the Institute for Biodiversity and Environment Research in Bariloche, Argentina, and a co-author of the new study, has conducted extensive field surveys, combing the Patagonian landscape where the cold-adapted yeast that he discovered seems to occur at a very high rate.
Despite their prevalence in Patagonia, the new study provides evidence that they are no longer exclusive to South America.
Hittinger and his group also discovered Saccharomyces eubayanus, with genetic hallmarks of the Patagonian strains, in a single North American location: Indian Mound Park, near Sheboygan, Wisconsin.
The study has been published in the journal Molecular Ecology.
