Genetically Modified Organisms in Agriculture

2026 Syllabus Objectives

By the end of these notes, you should be able to:

  1. Explain that genetic engineering may help to solve the global demand for food by improving the quality and productivity of farmed animals and crop plants, using the examples of GM salmon, herbicide resistance in soybean and insect resistance in cotton

  2. Discuss the ethical and social implications of using genetically modified organisms (GMOs) in food production

What Are Genetically Modified Organisms?

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Genetically modified organisms (GMOs) are living things whose DNA has been changed using genetic engineering techniques. This means scientists have added, removed, or altered specific genes to give the organism new characteristics.

GMOs can be divided into two categories:

  • Transformed organisms – organisms that have taken up a foreign gene (a gene from a different species) through genetic engineering
  • Transgenic organisms – organisms that not only contain the foreign gene but also actively use it to produce new proteins and show new characteristics

Important note: All transgenic organisms are transformed (because they contain a foreign gene), but not all transformed organisms are transgenic (some may take up the gene but not actually use it).

How Genetic Engineering Helps Solve the Global Food Demand

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The world's population is growing rapidly, and we need to produce more food to feed everyone. Genetic engineering can help solve this problem by:

  • Increasing crop yields – making plants grow bigger or faster
  • Reducing crop losses – protecting plants from pests and diseases
  • Improving animal productivity – making farm animals grow faster or produce more meat
  • Reducing the need for chemicals – creating plants that need less pesticide or herbicide

Let's look at three specific examples of how GMOs are helping to produce more food.

Example 1: GM Salmon (Aqua Advantage)

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The Problem

Normal Atlantic salmon takes about 3 years to grow to full mature size. This is because salmon only produce growth hormone during the warm seasons (spring and summer), so they only grow during these times. During autumn and winter, their growth stops.

This slow growth rate means:

  • Fish farms need to wait longer before they can sell the fish
  • Less fish can be produced per year
  • It costs more to feed and maintain the fish for 3 years

The Solution: Genetically Modified Salmon

Scientists created a genetically modified Atlantic salmon called Aqua Advantage salmon. This GM salmon reaches full mature size in just 1.5 years (18 months) – that's twice as fast as normal salmon.

How It Works

The GM salmon contains two foreign genes:

  1. A growth hormone gene from Pacific salmon – this gene tells the fish's body to make growth hormone
  2. A promoter from ocean pout (a type of fish) – this is like a "switch" that keeps the growth hormone gene turned on all year round

These two genes are inserted into a fertilized Atlantic salmon egg. When the egg grows into a fish, it produces growth hormone throughout the entire year, not just in spring and summer. This means the GM salmon keeps growing all year round.

How This Helps Food Production

  • Faster growth = fish can be sold sooner
  • More fish can be produced in the same amount of time
  • Lower costs because the fish need less food overall (they're eating for 1.5 years instead of 3 years)
  • More food available to feed the growing population

The GM salmon was approved for human consumption by the FDA (Food and Drug Administration) in the USA, making it one of the very few GM animals approved for eating.

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