Bite Me: The Mutation That Made Corn Kernels Consumable

A single point mutation in corn's ancestor teosinte got rid of the hard shell that used to encase every kernel.   

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Nothing says summer like a . But that treat would be much harder to eat if it weren’t for a crucial mutation. The change, in just one letter of the , appears to have cracked the hard casing that covered every kernel in corn’s wild ancestor. That’s according to a study in the journal . [Huai Wang et al, ]

Corn was domesticated from a wild grass called teosinte some 9,000 years ago. But how did our ancestors make maize the agricultural marvel it is today? Seems they selectively propagated plants with a particular mutation—one that made the kernels more accessible to hungry .

The researchers compared the DNA of 16 varieties of modern corn and 20 types of teosinte. And they found a single, key mutation that is present in modern corn but absent in its wild-grass ancestor. This genetic hiccup disrupts the activity of a protein called .

In teosinte, the protein directs the formation of a hard shell around every corn kernel. But the modern maize mutation gives a new set of marching orders. The mutant protein turns the ear inside out, converting the seed cases into a cob that holds all the kernels in place.

When the researchers reversed the effects of the mutant protein, the ancestral seed-case remnants started to reappear.

The results suggest that even minor genetic changes can lead to some pretty tasty developments. You might call it a-maize-ing. But that would be corny.

—Karen Hopkin