ABSTRACT

Throughout most of human history, humans manipulated the genetic makeup of crops and livestock without explicit knowledge of genetics. Farmers simply made the choice to plant seed or breed animals from the individuals or populations that demonstrated the most desirable characteristics, and this was enough to direct the evolution of domesticated species. Gradually, plant and animal breeding developed into a science as we learned more about the genetic basis of selection and began to direct it more specically to our advantage. Today, the elds of biotechnology and genetic engineering are rapidly expanding the power that humans have over the genomes of domesticated species, making it possible to incorporate traits and characteristics into plants and animals in ways and at rates never before possible.