All the plants and animals we eat and use came from somewhere. Chickens are related to a bird in Southeast Asia; wheat comes from some kind of middle Eastern grass. Years ago, genetic research found that corn’s closest ancestor was teosinte, a grass that grows in Mexico.
But this never quite made sense. Teosinte doesn’t look much like corn. And it’s inconvenient. Its seeds come to maturity gradually, rather than all at once like corn, so at any one time there aren’t many seeds to harvest. Why would early Americans have thought it was worth domesticating, 10,000 years ago? (If you want to know more about this, or if you just want to have your mind blown, you should read 1491.)
Smithsonian scientists have part of the answer: climate change. The climate was different then, with lower temperatures and less carbon dioxide in the atmosphere, and teosinte probably grew differently, according to their greenhouse experiments. I wrote about the study for ScienceNOW last week.
photo: John Doebley