Y
east is not typically considered a domesticated organism. Dogs, cats, and cows might come to mind first, but humans have nonetheless played an important role in the fungus’s evolution. A study in
published yesterday (December 9) reports that humans have caused most bread yeast strains,
Saccharomyces cerevisiae, to diverge into two distinct groups: one used in large-scale, industrial bread-making and one used in artisanal sourdough bread. While industrial strains start fermenting more quickly, sourdough yeasts have more copies of the genes responsible for metabolizing maltose, a process that typically happens later in the fermentation process and helps leaven the dough.