Last week I shared a discussion I'd had at a BASF science-focused event about genetic editing. Interesting stuff, and these days it can be more precise than ever, but we've been doing "genetic editing" by hand for a few thousand years. The latest evidence of that comes in a new report from the journal Genetics.
University of Wisconsin researchers had found that it was only a single gene mutation that made corn a lot different than its early ancestor. Most farmers know that 10,000 years ago corn was basically a grass called teosinte. It was a homely little plant, but the kernels it produced, once harvested, provided sustenance.
However, early plant breeders - ok picky farmers who kept selecting plants with bigger seed heads and other desirable traits - actually pushed through a single-gene mutation that rally made corn what it is today. Back in the distant past teosinte seeds had a seed case, like a mini walnut, protecting the soft seed inside. Corn doesn't have that, which results in those nice juice kernels on the cob that can be picked and shelled easily.
But those Wisconsin researchers wanted to know what genes made corn different. Some have postulated that as few as 6 genes make the difference between teosinte and today's corn plant. In this case, it is a one-gene issue with a mutation that switches one amino acid for another at a specific position in a protein regulation formulation of those seed shells.
Heady stuff, especially for busy farmers with summer work to consider. But think of it this way, one gene tga1 has a single change in corn that makes it totally different than tga1 in that ancestor teosinte. That single change made the difference. The trait got rid of the seed case, and kept the kernels firmly attached to the cob.
Those ancient plant breeders were able to develop a 'naked seed' teosinte and from that modern corn was evolved. I use "evolved" as a verb because in the last 10,000 years corn has been tweaked by any number of means to improve performance, food and feed quality. So when the anti-GMO'ers get going they act as if the corn they eat is some natural product - far from it.
In the release about this genetic find, the researchers explain that tga1 is like a conductor of an orchestra coordinating the actions of a lot of musicians. Says John Doebley, study leader: "The same orchestra can play in different ways, depending on the conductor's signals."
In teosinte, tga1 regulates genes in a way that helped those seed cases form. In corn, tga1 disrupts the process. The researchers wanted to know exactly what was different and what they found was fascinating. The corn tga1 essentially substitutes an amino acid in the gene for another - so a G gets replaced with a C. They also found that in corn tga1 was more like a "repressor" versus the teosinte version that was more like a "promotor" of genetic action.
A single gene change made a big difference in the eventual development of corn. If single gene changes are so powerful, this argues for continued increased precision in future breeding models. Who knows how researchers may be able to change the genetic makeup of a crop to enhance productivity, and profit, for the farm; and food quality and nutrition for consumers. Yet to meet growing food demand we need to use the tech that makes sense (thoroughly tested of course), and allow for its approval for use.