Over the Christmas holiday, quite a few of us will consume ethanol-containing products. This simple, two-carbon molecule is a potent (and legal) mood-altering drug that is woven into the fabric of European and many other cultures since time immemorial. Ethanol has been part of the furniture of human civilization since enterprising farmers discovered it in rotten fruit. It is only fitting that it features prominently at Christmas, a winter feast of excess.
When you first think of domesticated organisms, dogs might come to mind (our earliest domestication), or perhaps wheat, or cattle or rice. But you might easily overlook single-celled yeast: the key active agreement in both bread and alcohol, and a great enabler of the agricultural revolution in Europe.