This mixed-breed Chihuahua and Great Dane show the range of dog sizes produced by artificial selection

Selective breeding transformed teosinte's few fruitcases (left) into modern corn's rows of exposed kernels (right)

Artificial selection is the intentional breeding of plants or animals. It means the same thing as selective breeding and is an ancient method of genetic engineering.

Selective breeding is a technique used when breeding domesticated animals, such as dogs, pigeons or cattle. Some of these animals may have traits that a breeder will want to carry over to the next generation. The breeder will therefore select those animals to breed which have that quality, rather than those that do not.