A cob of maize holds several hundred kernels, and each one came from its very own fertilization. So you could think of the cob, perhaps, like a large, tight-knit family, full of unique kernel personalities: some purple, some yellow, some fat, some skinny.

In the 1940s, geneticist Barbara McClintock of the Cold Spring Harbor Laboratory in New York wanted to know: Why is it that some kernels show an uneven splattering of color? If the DNA in every cell in each kernel contains the same pigment gene (or genes), then why isn’t that color expressed the same way in every cell?

As McClintock would discover (and, three decades later, win a Nobel Prize for), the color variation in maize