BiologyExam code: 4BI1
Selective Breeding
Use of Biological Resources
Selective breeding is one of several ways humans have developed to produce useful plants and animals. The full picture includes:
| Technique | What it does | Speed | Genetic variation in offspring |
|---|---|---|---|
| Selective breeding (this topic) | Bring together desirable alleles already present in the species, generation by generation | Slow (many generations) | Some (offspring inherit a mix from two parents) |
| Tissue culture / cuttings (this topic + topic 12) | Make many genetically identical clones of a chosen plant | Very fast | None (clones) |
| Genetic engineering (topic 18) | Insert specific genes from another species directly into an organism's DNA | Fast at the lab stage | None (precise control) |
| Cloning of animals (topic 18) | Make genetically identical copies of a chosen animal | Fast at the lab stage but technically demanding | None (clones) |
Each technique has its place:
- Selective breeding is the traditional approach, slow but reliable, useful when many small improvements need to combine
- Tissue culture is best when a parent plant already has all the qualities you need
- Genetic engineering is best when you need a specific feature (e.g. a particular protein) that does not exist in the species
- Cloning is best when you have one outstanding individual whose exact genetic makeup you want to preserve
These topics will all come together in topic 18, which covers genetic engineering and cloning in detail.