Benefits, Risks and Ethics of Genetic Engineering Revision Notes | GCSE AQA Higher Biology

1. The Promise and Peril of Genetic Engineering

Scientists can now cut and paste genes between completely different species - inserting jellyfish genes into bacteria to make them glow, or human insulin genes into bacteria to mass-produce medicine. This power to rewrite the genetic code of life brings incredible opportunities, but also raises serious questions about safety and ethics.

The technique works by using enzymes to cut specific genes from one organism and insert them into another. The modified organism then produces the protein coded by the new gene, giving it new abilities it never had naturally.

2. Medical Miracles - Benefits in Medicine

Genetic engineering has revolutionised medicine by allowing mass production of human proteins that were previously impossible to obtain. Before genetic engineering, diabetics relied on insulin extracted from pig and cow pancreases - a limited and sometimes allergenic supply.

Now, human insulin genes are inserted into bacteria like E. coli. These modified bacteria become living factories, producing pure human insulin identical to what your pancreas makes. The bacteria multiply rapidly in fermentation tanks, creating unlimited supplies of life-saving medicine.

Other medical breakthroughs include human growth hormone for treating dwarfism, clotting factors for haemophiliacs, and vaccines produced in genetically modified yeast. These medicines are purer, safer, and more abundant than traditional alternatives.

3. Feeding the World - Benefits in Agriculture

GM crops tackle three major agricultural challenges: pests, diseases, and nutritional deficiencies. Bt corn contains genes from soil bacteria that produce a protein toxic to insect larvae but harmless to humans. This built-in pesticide reduces crop losses and chemical spraying.

Golden Rice addresses vitamin A deficiency, which causes blindness in 250,000 children annually. Scientists inserted genes from daffodils and bacteria to make rice produce beta-carotene (vitamin A precursor), giving the grains a golden colour.

Herbicide-resistant crops allow farmers to spray weeds without harming their crops. This increases yields and reduces the need for mechanical weeding, saving fuel and labour costs.

4. Environmental Concerns and Ecological Risks

Critics worry that GM crops could harm non-target species and disrupt ecosystems. Bt corn pollen was initially found to kill monarch butterfly caterpillars in laboratory studies, though field studies showed minimal real-world impact.

Herbicide-resistant crops can lead to 'superweeds' - wild plants that acquire resistance genes through cross-pollination. These weeds become harder to control and may outcompete native wildflowers, reducing biodiversity.

There are also concerns about effects on beneficial insects like bees and natural predators. Some studies suggest certain GM crops may reduce populations of insects that birds and other wildlife depend on for food.

5. Human Health Questions and Safety Concerns

Many people worry about the long-term effects of eating GM foods, though scientific consensus suggests they're as safe as conventional foods. The concern is that we don't have decades of data on human consumption.

Potential risks include new allergens - if genes from allergenic foods are transferred, they might trigger reactions in sensitive individuals. There are also theoretical concerns about antibiotic resistance genes used as markers during genetic modification.

However, extensive testing is required before GM foods reach the market. Regulatory agencies like the FDA and EFSA evaluate safety data for years before approval. No confirmed cases of harm from approved GM foods have been documented.

6. Ethical Dilemmas and Moral Questions

Beyond scientific concerns lie deeper ethical questions. Some religious groups view genetic modification as 'playing God' - interfering with natural creation in ways that cross moral boundaries.

There are also concerns about corporate control of food supply. A few large companies own patents on GM seeds, potentially giving them too much power over farmers and food production worldwide.

Economic justice issues arise when expensive GM technologies benefit wealthy farmers but remain inaccessible to poor farmers who might need them most. Some argue this widens the gap between rich and poor nations.

7. Weighing the Evidence - Exam Technique

Exam questions often ask you to evaluate genetic engineering by weighing benefits against risks. The key is presenting both sides fairly before reaching a balanced conclusion.

For 6-mark evaluation questions, structure your answer: state your position, give two supporting points with evidence, acknowledge the counter-argument, then conclude with a balanced judgement that weighs the evidence.

Worked example: Answering a 6-Mark Evaluation Question

'The benefits of genetic engineering outweigh the risks.' Evaluate this statement. [6 marks]

1. I agree that benefits currently outweigh risks, but with important caveats. — Take a clear stance - don't sit on the fence
2. GM insulin saves millions of diabetic lives and is safer than animal insulin because it's identical to human insulin. — Specific example with explanation of why it works
3. Golden Rice could prevent 250,000 cases of childhood blindness annually by providing vitamin A in rice. — Another concrete example with quantified impact
4. However, environmental risks like superweeds and effects on non-target species are genuine concerns that require ongoing monitoring. — Show you understand the other side
5. While risks exist, current evidence shows greater benefits, especially in medicine where alternatives don't exist. — Compare the magnitude of benefits vs risks
6. Benefits outweigh risks provided we maintain strict safety testing and environmental monitoring. — Qualified conclusion shows sophisticated thinking

Answer: A balanced evaluation that acknowledges both sides but reaches a reasoned conclusion based on current evidence.