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GCSE Biology · key term
Breeding between closely related organisms, which increases the chance that offspring inherit two copies of a harmful recessive allele.
Used by AQA, Edexcel and OCR
Specification 4.6.2.3 · Paper 2
Breeding between organisms that are closely related genetically.
Revise: Selective BreedingRepeatedly choosing a small number of similar individuals can mean breeding organisms that are closely related. This is inbreeding. Because relatives tend to share many of the same alleles, continued inbreeding can reduce the variety of alleles in the population: its gene pool becomes smaller.
Specification 4.14 · Paper 1
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Selective breeding may be acceptable when it improves disease resistance without reducing welfare or genetic diversity too far. It is harder to justify when an extreme characteristic causes suffering or when inbreeding creates a highly vulnerable population.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Breeding between closely related individuals, which increases the chance that offspring inherit harmful genetic variants.
Revise: Selective BreedingIf breeders repeatedly use only a small number of closely related parents, inbreeding can reduce genetic variation. Harmful inherited conditions may then become more common, and a population with little variation may be less able to cope with a new disease or environmental change. These are possible risks of how breeding is carried out, not unavoidable results of every selective-breeding programme.