Database results:
examBoard: Pearson Edexcel
examType: IGCSE
lessonTitle: Genetically Modified Plants
Genetic modification (GM) is a technology that allows scientists to change an organism's DNA in ways that wouldn't happen naturally. For plants, this means we can give them new traits to help them grow better, resist pests, or provide more nutrients. Unlike traditional breeding which mixes thousands of genes, genetic modification precisely changes specific genes.
Key Definitions:
Scientists modify plants for several reasons:
Creating a GM plant involves several key steps:
Scientists have developed several methods to insert new genes into plant cells. These techniques have become more precise over time, allowing for more targeted modifications.
There are several ways to get new genes into plant cells:
Uses a soil bacterium (Agrobacterium tumefaciens) that naturally transfers DNA into plant cells. Scientists replace the bacterial genes with the genes they want to insert.
Tiny gold or tungsten particles are coated with DNA and literally shot into plant cells. Some DNA enters the nucleus and integrates into the plant's genome.
Brief electrical pulses create temporary pores in cell membranes, allowing DNA to enter. Works well with plant cells that have had their cell walls removed.
Many GM plants have been developed and some are widely grown around the world. Here are some of the most significant examples:
Example: Roundup Ready Soybeans
These soybeans contain a gene from a soil bacterium that makes them resistant to the herbicide glyphosate (Roundup). Farmers can spray fields to kill weeds without harming the crop. This reduces the need for tilling, which can cause soil erosion.
Example: Bt Cotton
Contains genes from the bacterium Bacillus thuringiensis (Bt) that produce proteins toxic to certain insect pests but harmless to humans. This reduces the need for chemical insecticides, saving farmers money and reducing environmental impact.
Example: Golden Rice
Contains genes from daffodils and bacteria that allow the rice to produce beta-carotene, which our bodies convert to vitamin A. Developed to address vitamin A deficiency in countries where rice is a staple food.
Example: DroughtGard Maize
Contains a gene that helps the plant cope with water shortage by slowing growth during drought conditions rather than dying. This allows the plant to survive until rain returns.
Bt cotton was introduced in India in 2002 and now accounts for over 90% of cotton grown there. The technology has:
However, there have been concerns about the high cost of GM seeds and whether small-scale farmers can afford them. Some also worry about pests developing resistance to the Bt toxin over time.
Like any technology, genetic modification of plants comes with potential benefits and concerns that need to be carefully considered.
Before GM plants can be grown commercially, they must go through extensive testing and regulatory approval. Different countries have different approaches to regulation.
In the UK and EU, GM crops undergo rigorous safety assessments including:
Only after passing these tests can a GM crop be approved for cultivation or import. Products containing GM ingredients must be labelled in the UK and EU, allowing consumers to make informed choices.
Golden Rice is a GM variety developed to address vitamin A deficiency, which affects millions of children worldwide and can cause blindness and death. Despite being developed in 2000, it was only approved for commercial growing in the Philippines in 2021.
The long delay highlights some challenges facing GM crops:
Supporters argue that Golden Rice could save thousands of lives, while critics question whether it's the best solution to vitamin A deficiency compared to promoting diverse diets or traditional vegetables rich in vitamin A.
Genetic modification technology continues to advance, with newer techniques offering more precise ways to edit plant genomes.
CRISPR-Cas9 is a newer gene-editing tool that allows scientists to make changes to DNA with greater precision than ever before. Unlike traditional GM methods that insert foreign DNA, CRISPR can make small edits to a plant's existing genes.
Potential applications include:
Some countries are regulating CRISPR-edited plants differently from traditional GM plants if they don't contain foreign DNA, potentially speeding up development and approval.
When thinking about GM plants, it's important to consider various ethical perspectives:
There are no simple answers to these questions and different people and cultures may have different views based on their values and priorities.
Log in to track your progress and mark lessons as complete!
Login NowDon't have an account? Sign up here.