Key Knowledge:
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Genetic modification describes the alteration of a genome using artificial genetic engineering technologies
- This is typically achieved by the addition or silencing of a specific gene such that a characteristic is either gained or lost
- To be identified as a genetically modified organism (GMO), the change should be heritable (able to be passed on)
Transgenics is a type of genetic modification where DNA is introduced from an unrelated species
- Hence, not all genetically modified organisms will necessarily be transgenic organisms (but all transgenic organisms are GMOs)
GMOs
Genetically modified organisms are used in agriculture and farming to address a variety of specific issues, including:
- Malnutrition: Golden rice has been engineered to produce high levels of vitamin A (which helps to prevent blindness)
- Pollution: Grains / cereals have been engineered with a low phytic acid content (when in manure, it pollutes soils and waterways)
- Longevity: Flavr Savr tomatoes have been engineered to have an increased shelf life (by deactivating the genes for ripening)
- Pest resistance: Bt corn has been engineered to be toxic to the European corn borer (a pest species that feeds on maize crops)
- Disease resistance: Blight resistant potatoes have been engineered (by including genes that trigger an immune defence to blight)
- Yield: Crops have been engineered to produce higher quantities or grow in adverse conditions (e.g. in arid or saline environments)
Implications
The use of GM crops is a highly contentious issue, as any potential benefits must be weighed against all of the possible risks
- When assessing the impact of a GM crop it is important to consider potential health, economic and environmental implications
GM Crops and Human Health
- GM crops can be used to improve human nutritional standards, by incorporating genes for certain proteins, vitamin or vaccines
- Additionally, GM crops can be manufactured that lack common natural allergens or toxins
- However, the inclusion or removal of certain genes could trigger unexpected adverse health reactions in some individuals
- Currently, not all foods with GM components are labelled, making informed decisions of use difficult for consumers
GM Crops and Economic Consequences
- GM crops can include genes to enable them to grow in a wider range of environments (e.g. drought / frost / salinity resistance)
- GM crops can be manufactured to produce greater yields (crops can potentially grow larger and faster)
- GM crops can include genes which slow the rate of spoiling, leading to longer shelf lives for GM foods
- GM crops may possess resistance to certain viruses or produce toxins to pests (reducing need for the use of pesticides)
- Herbicide resistant crops can be used to allow for the easier killing of weeds (which compete with crops for soil nutrients)
- Overall, an improved yield, reduction in farming costs and ability to farm more land will provide an economic benefit to farmers
- However, patent protection allows biotech companies to restrict the use of seeds and force farmers to pay high prices for use
GM Crops and Environmental Issues
- The ability to farm a wider range of environments with GM crops will potentially reduce the need for associated deforestation
- Also, the generation of pest-resistant crops means that less chemical insecticides will be released into the environment
- However, GM crops could potentially reduce biodiversity in a region by competing with indigenous plant life
- Furthermore, proteins or toxins produced by GM crops could negatively affect certain organisms within the ecosystem
- Cross-pollination by GM crops could also result in the formation of herbicide-resistant weeds and grasses
- GM crops with pest toxins could also accelerate the evolution of resistant pest species
Summary of Issues Associated with Genetically Modified Crops
