Been baking during the pandemic? Here's where your yeast comes from

The story behind the fungus in your dough

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Harry Thaker on Unsplash 

With us all spending a lot of time at home recently, many have picked up new hobbies, like cooking and baking. This has led to some of us becoming friends with Saccharomyces cerevisiae, a single-celled fungus known as baker’s yeast. This new friend may be tiny, but baker’s yeast arguably contends with dogs for the title of man’s best friend. 

S. cerevisiae has been associated with human culture for thousands of years for its use in fermentation, a process used in making alcoholic beverages and baking. Biological research has progressed in many areas because this organism is so commonly used to understand cellular and molecular biology. For all that society uses S. cerevisiae, you have to wonder, where did the yeast come from?

Originally, researchers hypothesized its origin to be from China/Far East Asia after discovering wild yeast in primeval forests from that area. In a more recent study, researchers found more evidence supporting that origin story comparing the genome of the discovered wild yeast and known domesticated yeast.

The researchers compared 106 wild and 260 domesticated yeast strains by phylogenetic analysis, or comparing family trees based on DNA sequence. They saw evidence of reduced genetic diversity in the domesticated yeast compared to the wild lineages. This suggests a founder effect — when an entire population descends from only a few individuals of an original population. Finding this founder effect implies that originally yeast were domesticated in China/Far East Asia. After early domestication, the dispersal and diversification of those yeasts is hypothesized to have led to the massive global collection of all other domesticated strains that we use today. Further analysis with even more domesticated and wild yeast from all over the globe will help further support this hypothesis.

So the next time you’re in the kitchen with your new friend, let them know they have a place to call home.