Selective breeding or artificial selection is when humans breed plants and animals for particular genetic characteristics. Humans have bred food crops from wild plants and domesticated animals for thousands of years.
Selective breeding takes place over many generations. These are the main steps for both plants and animals:
Farmers selectively breed different types of cows with highly desirable characteristics in order to produce the best meat and dairy. Characteristics can be chosen for usefulness or appearance.
Desired characteristics in plants:
Desired characteristics in animals:
The new varieties may be economically important. For example, they may provide more or better quality food, or allow farmers to feed more people.
Because of selective breeding, future generations of selectively bred plants and animals will all share very similar genes which will reduce variation. Genes and their different alleles within a population are known as its gene pool. Inbreeding can lead to a reduced gene pool, making it more difficult to produce new varieties in the future. This also makes organisms prone to certain diseases or inherited defects.
Benefits of selective breeding include:
Risks of selective breeding include: