When humans began to farm between ten and twenty thousand years ago, they took the seeds from their best edible wild plants and sowed them to create crops. Early farmers selected the most desirable plants to provide seeds for the next year’s crop. They looked for faster growth, higher yields, larger seeds, tastier fruit, bigger plants, resistance to insects, other pests, and disease, and other desirable traits. One of the most important traits was that the plants didn’t make them sick. Eventually they learned that plants within the same species, and in the 1700’s, across different species could be artificially mated or cross-pollinated to improve the characteristics of the plant.
These farmers knew nothing of genes, of course, but were actually altering the genetic makeup of the plants.
Read the full, original story here: “Can you describe in detail the process by which genes are altered in foods?”