BiologyExam code: 4BI1
Genetic Engineering
Use of Biological Resources
Genetic engineering and selective breeding both aim to produce organisms with useful new traits. They achieve this in very different ways.
| Feature | Selective breeding | Genetic engineering |
|---|---|---|
| What it does | Combines existing alleles already in the species through generations of choosing parents | Inserts specific genes (from any species) directly into the DNA |
| How long it takes | Many generations (often years to decades) | Fast at the lab stage (days to weeks for bacteria) |
| Source of new traits | Alleles already present in the species, brought together by breeding | Genes from any organism, even different kingdoms |
| Precision | Imprecise: many genes are shuffled together at each cross, and offspring inherit a mix | Very precise: only the specific gene wanted is moved |
| Risk of unintended changes | Lower (genes from same species are well-tested) | Higher in principle (foreign DNA in new context can have unexpected effects) |
| Public acceptance | Widely accepted (10 000 years of tradition) | Controversial; many people are wary of "unnatural" GM food |
| Examples of products | Modern wheat, dairy cattle, dog breeds | Insulin-producing bacteria, Bt crops, golden rice |
The two techniques can be combined. Genetic engineering can introduce a useful gene; selective breeding can then improve other characteristics over generations.