Discovering the code
Every cell of all living things contains DNA, which is a code of instructions that tell the cell how to function.
Components of DNA, called genes, determine the traits of an animal like its height, its hair color, whether or not it grows horns and to what diseases it is susceptible or resistant. Most traits are passed along to future generations from parent to child, and some are more desirable than others.
Within agriculture, animal breeding and traditional selection are intentional in order to bring forth the best attributes to the next generation. From the first-time we domesticated animals thousands of years ago, either knowingly or not, they were selected for desirable traits that we considered important.
Through trial and error, farmers have set out to raise the best, most healthy food animals without sacrificing the good qualities they already have.