Advertisement

Scientists detail the gene behind corn's world dominance

Researchers previously traced maize's roots to a weedy teosinte variety native to a valley in southwestern Mexico. Now they've identified the vital genetic mutation that happened there.

By Brooks Hays
The hard coated kernels and small husks of teosinte, corn's wild ancestor. Photo by UW-Madison/Doebley
The hard coated kernels and small husks of teosinte, corn's wild ancestor. Photo by UW-Madison/Doebley

MADISON, Wis., July 27 (UPI) -- Corn is world's most prolific and valuable crop. But what is responsible for the grain's dramatic ascension? That's what researchers at the University of Wisconsin wanted to know. And find out, they did.

According to a new study, a single switch in the genetic coding of teosinte, corn's ancient ancestor, turned what was an inedible wild grass into a viable sustenance crop.

Advertisement

Just one nucleotide change to the grass's glume architectural gene, known as tga1, coaxed teosinte's kernels into ditching their hard outer shell, exposing the yummy insides to humans and animals.

Researchers previously traced maize's roots to a weedy teosinte variety native to a valley in southwestern Mexico. Here, scientists said, was the birthplace of corn. But what enabled the transformation? Why does maize, tall and erect, look so much different than the weedy grass with only miniature bulbs of kernels?

In comparing the genomes of maize and teosinte, researchers noticed a difference in the type of protein signaled by gene tga1. It turned out, tga1 was a rather important gene.

"A series of experiments showed that this particular gene, tga1, is a master regulatory gene -- a conductor of the orchestra," study author John Doebley, a professor at Wisconsin, explained in a press release.

Advertisement

A single mutation to tga1 changed the way its protein behaved, and thus augmented the way a variety of genes are expressed.

"Each musician is a target gene and the conductor is telling each one what to play and how loud to play," said Doebley.

The key augmentation, in this instance, was the protein's refusal to signal the genes previously responsible for the production of the kernels' hard outer coating.

"So, the kernel ends up naked, uncovered and exposed on the surface of the corn cob, to be eaten," Doebley explained.

The new research was published in the journal Genetics.

Latest Headlines