Selective breedingSpec 4.6.2.3
Selective breeding (artificial selection) is the process by which humans breed plants and animals for particular genetic characteristics. Humans have been doing this for thousands of years, since they first bred food crops from wild plants and domesticated animals.
- Choose parents with the desired characteristic from a mixed population.
- Breed them together.
- From the offspring, choose those with the desired characteristic and breed them together.
- Continue over many generations until all the offspring show the desired characteristic.
The characteristic can be chosen for usefulness or appearance. Examples:
- disease resistance in food crops
- animals which produce more meat or milk
- domestic dogs with a gentle nature
- large or unusual flowers.
Impact of selective breeding
| Benefits | Risks |
|---|---|
| Crops and animals that give higher yields of food | Can lead to inbreeding, where some breeds are particularly prone to disease or inherited defects |
| Disease-resistant crops | Reduces the number of different alleles in the population, because only a few individuals are bred |
| Animals or plants with useful or attractive features | Some people have ethical objections to animals being bred for human use |