Genetic Modification
Genetic modification involves moving bits of DNA between organisms. It's used in agriculture to produce bigger, tastier plants. It’s also used in the pharmaceutical industry to make insulin.
Genetic modification
Here's how you would make a GM organism:
Cut out the useful gene using restriction enzymes
Use the same restriction enzymes to cut the plasmid
This should create complementary sticky ends (overhanging bases)
Join the gene of interest with the plasmid using the enzyme DNA ligase
The gene should now be part of the plasmid — this is called recombinant DNA
The recombinant plasmid is taken up by bacteria, which will express the gene and build the protein that it codes for.
For example, this is how insulin is made.
The insulin gene is removed from human DNA using restriction enzymes.
A plasmid is also cut with restriction enzymes.
DNA ligase joins the complementary sticky ends to form the recombinant DNA.
The recombinant plasmid is taken up by bacteria.
The transgenic bacteria are grown in large fermenters to produce large amounts of insulin, which can then be extracted.
Insulin produced in this way can be purified and used as a treatment for diabetes. Compared to the old method of insulin production — extracting it from the blood of livestock — this is cheaper and more ethical. Human insulin also works more efficiently in our bodies than insulin taken from pigs and cows.
Genetically modified crops
Genes can be inserted into plant species to provide:
Resistance to insect attack
Herbicide resistance
Increased yield
Higher nutritional content
The beta-carotene gene was added to wild rice, to create a new strain called golden rice with increased nutritional value. Beta carotene is used to synthesise vitamin A which is needed for healthy vision. Golden rice can be used in areas where vitamin A deficiency is common to protect against blindness.
Ethical issues with GMOs
Many people are opposed to the use of genetically modified organisms and GM-products are heavily regulated by government agencies. The main objections include:
They may produce unknown health risks, such as allergies.
The gene may accidentally be transferred to other plants by cross-pollination — this is known as gene flow.
GM crops could reduce biodiversity. For example, plants genetically modified to release insecticides will kill insect populations.
Religious reasons — do humans have the right to create new lifeforms?
The seeds for GM crops are patented and may not be affordable for farmers in developing countries.