John Morrissey, writing at Phys.org:
Historians often trace the dawn of human civilization back 10,000 years, when Neolithic tribes first settled and began farming in the Fertile Crescent, which stretches through much of what we now call the Middle East. Prehistoric peoples domesticated plants to create the cereal crops we still grow today, and in the Zagros mountains of Iran, Iraq and Turkey, sheep, goats and cows were bred from their wild relatives to ensure a steady supply of meat and milk. But around the same time as plants and animals were tamed for agriculture, long before anyone even knew of microscopic life, early humans were domesticating microbes too.
In a paper published in Current Biology, we discovered how “milk yeast”—the handy microorganism that can decompose lactose in milk to create dairy products like cheese and yogurt—originated from a chance encounter between a fruit fly and a pail of milk around 5,500 years ago. This happy accident allowed prehistoric people to domesticate yeast in much the same way they domesticated crop plants and livestock animals, and produce the cheeses and yogurts billions of people enjoy today.
Well this sounds a bit interesting, let’s learn more:
Kluyveromyces lactis, or milk yeast, is found in French and Italian cheeses made from unpasteurized milk, and in natural fermented dairy drinks like kefir. But the ancestor of this microbe was originally associated with the fruit fly, so how did it end up making many of the dairy products that people eat today? We believe milk yeast owes its very existence to a fly landing in fermenting milk and starting an unusual sexual liaison. The fly in question was the common fruit fly, Drosophila, and it carried with it the ancestor of K. lactis. Although the fly died, the yeast lived, but with a problem—it could not use the lactose in milk as a food source. Instead, it found an unconventional solution—sex with its cousin.
Okay, I think I’m finished with the internet for tonight.