Selective breeding, also known as artificial selection, is a process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits by choosing which typically animal or plant males and females will sexually reproduce and have offspring. The process involves choosing parents with particular characteristics to breed together and produce offspring with more desirable traits. Here are some key points about selective breeding:

• An organism’s characteristics are partly determined by the combination of gene variants that are passed on from one generation to the next.
• Selective breeding often involves breeding individuals that are closely related, known as inbreeding.
• Selective breeding often results in a population of animals or plants with very similar genetics, which means that the population will have the same strengths but also the same weaknesses.
• Selective breeding programs that concentrate on a small subset of genes determining a limited group of desired characteristics often use a small number of individuals as the "founder population" for all the descendants. While considerable care is taken to produce individuals homozygous for the desired characteristics, there are many other genes that also end up being homozygous within the small group of inbred founders. Some of these genes have deleterious effects, and their adverse conditions tend to be disproportionately common in the members of populations derived from a small founder group.
• Although both selective breeding and genetic engineering change an organism’s genetic characteristics, they are different processes. Selective breeding makes use of existing, naturally present gene variants in a species and the natural process of breeding, while genetic engineering involves a direct change to an organism’s genome in the laboratory.

Selective breeding has been used for centuries to develop new breeds of animals and plants with desirable traits. Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book, On the Origin of Species.