Selective breeding

Selective breeding

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, e.g. the breeding of food crops from wild plants and the domestication of animals.
Selective breeding involves:
- Choosing parents with a desired characteristic from a mixed population and breeding them together.
- Choosing the offspring with the desired characteristic and breeding them together.
- Repeating the cycle over many generations until all offspring show the desired characteristic.
The characteristic can be chosen for its usefulness or appearance:
- Animals that produce more meat or milk.
- Disease resistance or increased size in food crops.
- Domestic dogs with a gentle nature.
- Large or unusual flowers.
Disadvantages of selective breeding:
- Can lead to ‘inbreeding’ when the parents are genetically very similar, where some breeds are especially prone to inherited defects or disease.
- Reduced genetic variation means that a change in the environment or a disease is more likely to kill an entire population.
- Physical problems in organisms, e.g. cows weighed down by large udders.
- The breeding method (e.g. artificial insemination) can be seen as unethical.

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