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Don't be fooled! The yellow or white corn you see in the grocery store is only the tip of the rainbow-colored iceberg of corn coloration. And these more genetically diverse varieties of corn might just save our husks one day.

Hosted by: Stefan Chin

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This episode is brought to you by Nature’s Fynd, a fungi-based food company for optimists.

Click the link in the description to discover the science behind Nature’s Fynd fungi-based foods. [♪ INTRO]. If you pick up some corn at the grocery store, odds are the kernels are yellow or white.

So you might just think that’s the color corn or maize, as it’s more commonly known around the world. But check this out. It’s called Glass Gem corn, and that rainbow is a breathtaking display of the natural genetic variation that exists for maize.

This extra-colorful corn exists thanks to one man’s journey to connect with his Cherokee heritage — as well as some neat aspects of maize genetics. The varieties of maize grown on a large scale are carefully bred to have cobs that are all the same size and shape and ready to harvest at the same time. And while that helps ensure high yields and efficient processing, it also means less diversity at the genetic level.

And slight variations in genes can make all the difference when it comes to resisting a pest or tolerating drought conditions. So these homogeneous crop varieties are more vulnerable to all sorts of threats. But, lucky for maize, not everyone prizes such a shallow gene pool.

Even though you don’t run into them every day, there are dozens of distinct kinds of maize and countless sub-varieties grown around the world, mostly on a small scale. In fact, people have been growing maize for thousands of years. And in many cultures, including Native American ones, maize is more than a crop — it’s an important part of their culture and heritage.

That’s where the story of Glass Gem begins. Several decades ago, a man named Carl Barnes started growing corn varieties in a more traditional way, as a way of connecting with his Cherokee heritage. Because of that, he focused on growing older varieties, including some that he collected from friends who belonged to different Native tribes.

Many of these varieties were bred to do better in diverse environments and for different uses. Like different corns for popping, eating fresh, or grinding for flour. And Barnes grew lots of these different corns together and let them cross-pollinate like his ancestors did.

This let their genes mingle and expanded the gene pool. He also took a special interest in saving seeds that showed unusual and interesting colors. He passed some of these to a friend, who then passed them along to another friend, who mixed them with a couple more varieties for good measure and grew them on a larger scale.

And all of this reclaiming, interbreeding, and seed exchange was the key to making the beautiful rainbow of Glass Gems! Now, no one has specifically looked into the genetics of Carl’s corn. But scientists have mapped the maize genome.

And we know that kernel color comes from colorful molecules called pigments. These pigments are produced by enzymes that work together sort of like a chemical assembly line. And those enzymes are coded for in the plant’s DNA.

There are also other genes whose products switch parts of the assembly line on or off. So differences in any of these genes can affect kernel color! And not only can variously colored pigments be present, absent, or present in different amounts, they can form in different tissue layers of the kernel, which adds interesting visual effects and more variation.

For instance, the starchy interior of the kernel ranges from white to deep yellow, depending on the amount of yellow carotenoids in it. Other colors come from anthocyanins in one or both of the kernel’s thin outer layers. These pigments come in reds, purples, and blues, and the intensity can range from nearly black to the pale pastels you see in Glass Gems.

And you get even more variation by laying them over each other. Like, a pale blue outer layer over a yellow interior could make a kernel look green. As for each kernel being different well, that’s because they’re all separate individuals... like, siblings.

You see, each ear is actually a whole bunch of female reproductive tracts stuck together. Those hairy parts, called silks, are like direct pipelines, each to a separate womb of sorts containing an egg with a unique combination of half the plant’s genes. That’s the future kernel.

Meanwhile, the tassel at the top of the plant contains the male reproductive bits. That’s where all the pollen is made. And each pollen grain also has a unique combination of half the plant’s genes.

Now, pollen travels on the wind. It scatters across a field. And if a pollen grain manages to land on a silk, it travels down and its genes unite with the egg’s.

So one plant’s pollen can land on a bunch of different ears. And each silk could, theoretically, receive pollen from a different plant. Which means each kernel not only has a unique mix of genes from its parents, each one can have a different father!

This is also true on big farms. But, because all the plants are so genetically similar, you don’t end up with much kernel variety in each cob. Barnes was growing multiple kinds of maize.

So there was a ton of genetic variation within his fields. And the mixing and matching of these brought all sorts of different gene combinations together! That’s ultimately how his corn ended up so colorful.

Sadly, Carl Barnes passed away in 2016, but his amazing corn lives on. You can even buy it and grow it yourself! And all the heirloom varieties and cross-pollination he fostered didn’t just make for prettier fall decor they also help give maize a better chance of surviving long term.

The varieties that are grown on a large scale aren’t just uniformly colored. They tend to be more genetically uniform in all ways, so they’re more uniformly vulnerable to threats like drought, pests, and disease. But other varieties carry variations in thousands of genes that underlie important crop traits.

Barnes was part of a renewed movement to preserve this genetic diversity. Today, there are seed-saving programs in place to catalog and store traditional and regional varieties. And farmers in some places never stopped growing maize the old way!

Like Barnes with his open pollinated fields and seed sharing, they recognize that maize benefits from spreading its genes. And unlike seed banks, these farmers keep diverse varieties alive and evolving. Chances are, we’ll need some of that diversity someday, when a nasty pest comes along or something else threatens to wipe out this staple crop.

So we should be grateful to Barnes and all the other farmers out there who are keeping the world’s corn delightfully colorful. Now, maize isn’t the only crop likely to face threats in the future. Our changing climate threatens basically everything that we’re growing.

But there are some yummy sources of protein that can take the heat… like fungi! Thanks to a breakthrough in fermentation technology, the folks at Nature’s Fynd are turning a fungi with origins in Yellowstone National Park into delicious, protein-packed foods that are both meat and dairy free. I really enjoyed getting to try Nature’s Fynd meatless breakfast patties.

I love a good breakfast patty and these ones give you that salty, savory flavor that you’re looking for. You can click on the link in the description to check out the science behind their fungi-based foods, or follow with their story over on Instagram! [♪ OUTRO].