Selective Breeding and Genetic Engineering

This lesson covers two ways humans intentionally alter the genetics of organisms: selective breeding (artificial selection) and genetic engineering. For AQA GCSE Biology, you need to understand how each process works, their advantages and disadvantages, and the ethical issues surrounding genetic engineering.

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Selective Breeding (Artificial Selection)

Selective breeding (also called artificial selection) is the process by which humans choose organisms with desirable characteristics to breed together. Over many generations, the frequency of the desired trait increases in the population.

How selective breeding works:

1. Choose individuals with the desired characteristic from the population
2. Breed these individuals together
3. Select the offspring that show the desired characteristic most strongly
4. Repeat over many generations until the trait is consistently expressed

graph TD
    A[Identify desired characteristic] --> B[Select individuals showing the trait]
    B --> C[Breed selected individuals together]
    C --> D[Select best offspring]
    D --> E[Breed selected offspring together]
    E -->|Repeat over many generations| D
    D --> F[Desired trait becomes common in population]

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Examples of Selective Breeding

Selective breeding has been used by humans for thousands of years:

In Plants