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Despite all the recent ballyhoo behind IPAs and other ales across the globe, the lager is still king. In America, all 20 of our top-selling beer brands from Bud Light to Dos Equis are lagers. And yet, despite our renewed interest in ales, the history behind those mass market lagers is probably more intriguing.

Though commonplace now, lagers were borne of innovation, albeit innovation that happened back in the 15th century. Before then, all beers were pretty much ales—using top fermenting yeast in warmer temperatures—until some Bavarian monks figured out how to use a hybridized yeast to brew lagers at cooler temperatures. But where did these crazy new lager yeasts come from?

A research team led by biologists at the University of Wisconsin-Madison—a school where beer is apparently never far from their minds—has been working to unravel the genetic history behind lager yeast. In a paper recently published in the journal Molecular Biology and Evolution, they claim to have made an interesting discovery: Two major strains of lager yeast, Saaz and Frohberg, that their team looked at actually came from two different sources—“multiple hybridization events,” as they called it.

“Lager yeasts did not just originate once. This unlikely marriage between two species, genetically as different from one another as humans and birds, happened at least twice,” co-author Chris Todd Hittinger was quoted as saying.

Outside of purely academic interest, Hittinger suggests the findings could have modern ramifications. “It raises the question: In the entire population, are there additional variants that might be useful? Is it an accident of history what gets hybridized?”

Compared to ale yeast, lager yeast is only about 500 years young. Maybe it still has some innovation up its sleeve?