Join High Touch High Tech in celebrating
Popcorn Lover’s Day
March 11, 2021
A humble ear of corn (a.k.a. Maize) might not seem like much. Maize is so ubiquitous in the modern world, not just in that tasty, crunchy popcorn bucket you get with extra butter at the movies, but in corn-based snacks and cereals, as corn starch, and as the primary animal feed for today’s massive factory farm operations. Throw in the fact that Ethanol is made from Maize and you could say that the world literally runs on it. The versatile and incredibly tasty Maize plant also represents a fascinating tale of scientific mystery – with an order of popcorn thrown in. The mystery of Maize was only solved when geneticists, biologists, and archaeologists united to unravel the true story of its domestication.
The domestication of crops for human consumption has taken place all over the world, with different cultures domesticating local plants independently, selecting them over generations for bigger fruit or more hardiness until they evolved into the fruits and vegetables, we buy in the supermarket today. The ancestor of wheat is visually similar to domestic wheat. The ancestor of an apple looks like an apple. Even the ancestor of watermelon is recognizable. But for a long time, no one knew where corn came from. Its wild ancestor was not apparent, and many thought it was extinct. By the mid-20th century, George Beadle, a giant in the emerging field of genetics and later winner of the Nobel Prize, had a theory: domestic corn came from a grasslike plant known as Teosinte, native to Mexico.
Teosinte vs. Corn
Teosinte is a bushy, branching plant that looks nothing like the single-stalked corn plant. It has a fruit that looks like a stick of small grass seeds, encased in a pod so hard it can easily crack a human tooth. Beadle embarked on a massive cross breeding operation and proved that the genetic differences between Teosinte and Maize were only five genes. The next generation of geneticists discovered that these five genes were regulatory genes, meaning that one single gene could control huge changes in the plant. Geneticists further theorized that Teosinte and Maize must have diverged about 9,000 years ago. The next step was to find evidence of where and when the use of Teosinte was adopted by humans.
Amazing archeological detective work in Mexico did not seek needle-in-a-haystack examples of fossilized grains. It was directed at analyzing ancient stone grinding tools for “microfossils” of grains still on them. On ancient stone tools, researchers found evidence that Maize was consumed starting around 9,000 years ago, just as geneticists predicted. It became clearer that Teosinte was the ancestor of Maize. One more question remained: how did people figure out that Teosinte could even be consumed? The seeds are so hard and inaccessible, not to mention tiny. Then someone in a lab tossed some Teosinte seeds into hot oil and the rest is history. It turns out that Teosinte pops just as popcorn today does, leaving a tiny but delicious popped treat where once there was an impossible kernel. Without popcorn (well, popteosinte) we would not have the agricultural abundance of Maize that supports so much of our life today!
Thinking of how the mixture of two ingredients creates a reaction (oil + kernel = popcorn), we took a dive into our experiment bank to see if we could find something similar. You are in luck, because we are dusting off our “Bang in a Bag” at-home experiment for you to test the theory of mixing two ingredients to create a REACTION! Check out the lesson plan below, grab your supplies, & have an explosively FUN time! https://sciencemadefun.net/downloads/Bang%20in%20a%20Bag_EOTD_May%2012th.pdf
Sources:
Learn more about Maize’s impact on global history:
https://www.youtube.com/watch?v=i6teBcfKpik
The amazing genetic detective work on Maize’s origins:
https://www.youtube.com/watch?v=mBuYUb_mFXA
An Indigenous American perspective on Maize:
https://www.youtube.com/watch?v=AMIuem1J3OQ
