About ten thousand years ago, humans first began to cultivate wheat, barley, and other grain-producing plants.
Planting settled crops helped transform small groups of foragers into a large population, living in villages and cities. They were able to all that thanks to one particular plant gene; a gene that protects grains against a deadly fungus, that could destroy entire crops.
The gene, called HM1, was first discovered in corn.
Scientists suspected that the same gene was active in wheat, barley, rice, and sorghum. To test the theory, researchers turned off the HM1 gene in one group of barley plants, and left the gene intact in others. When the barley was exposed to the fungus, the plants without the gene were damaged, however, the barley with the gene remained unscathed.
So why does this matter? Well, without the gene's protection, grains may not have survived as well as they have for tens of millions of years. Without an abundance of grains, humans might not have begun to cultivate them and invent agriculture. Without the agriculture, there's no way to produce enough food to feed large groups of people living in villages, towns, and cities.
If not for the hardiness of grains, and their ability to thrive in many different parts of the world, humans may never have evolved beyond small groups of hunter-gatherers.