GM organisms and crop plantsSpec 4.12B
A well-known example is the introduction of a gene from the bacterium Bacillus thuringiensis (Bt) into crop plants. The gene codes for a toxin that kills many insect pests. Plants with the gene make the toxin themselves and so have insect resistance.
| Advantages | Disadvantages |
|---|---|
| Less crop is lost to pests, so yields are higher | Possible risk to human health, which some people worry about |
| Less insecticide needs to be sprayed, which saves money and reduces damage to other organisms | Genes may spread to wild plants, and the toxin might harm other insects |
| Crops can be given extra characteristics, such as greater nutritional value or resistance to disease | GM seeds can be expensive, and farmers may have to buy new seeds each year |
| More food can be produced for a growing population | Concerns that it is wrong or unnatural to change organisms' genes |
| Crops with a gene for herbicide resistance can be sprayed to kill weeds without harming the crop | Insect pests may evolve resistance to the Bt toxin by natural selection |
Quick check
What is genetic engineering?
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Modifying the genome of an organism to introduce desirable characteristics.
What does a GM organism contain that a normal organism does not?
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A gene transferred from another organism.
Give one example of a desirable characteristic introduced by genetic engineering.
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For example, bacteria making human insulin, or crop plants resistant to insects.