Selective Breeding and Genetic Engineering

This lesson covers how humans use their understanding of genetics to modify organisms for useful purposes. You need to understand selective breeding and genetic engineering, including their benefits, risks and ethical implications. These are key topics in the AQA GCSE Combined Science Trilogy specification (8464).

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Selective Breeding (Artificial Selection)

Selective breeding is the process by which humans choose organisms with desirable characteristics to breed together. Over many generations, the frequency of the desired characteristic increases in the population.

The Process

1. Choose parents with the desired characteristic from the existing population
2. Breed these selected individuals together
3. Select the best offspring — those that show the desired characteristic most strongly
4. Repeat the process over many generations until the desired trait is consistently present

graph TD
    A["Identify desired<br/>characteristic"] --> B["Select parents with<br/>that characteristic"]
    B --> C["Breed selected<br/>parents together"]
    C --> D["Select best offspring<br/>showing desired trait"]
    D --> E["Breed selected<br/>offspring together"]
    E --> F["Repeat over many<br/>generations"]
    F --> G["Population consistently<br/>shows desired trait"]
    style A fill:#bbdefb,stroke:#1565c0
    style B fill:#c8e6c9,stroke:#2e7d32
    style C fill:#fff9c4,stroke:#f9a825
    style D fill:#ffccbc,stroke:#d84315
    style E fill:#e1bee7,stroke:#6a1b9a
    style F fill:#b2dfdb,stroke:#00796b
    style G fill:#c8e6c9,stroke:#2e7d32

Examples of Selective Breeding