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Genetic engineering is also called genetic modification or GM. It involves modifying the genome of an organism by introducing a gene from another organism to result in a desired characteristic.

An organism which has been modified to include genetic material from another organism is a transgenic organism.

Genetic engineering involves these steps:

1. selection of the desired characteristic
2. the gene responsible for the characteristic is 'cut out' of the chromosome
3. the gene is transferred and inserted into another organism
4. replication of the modified organism

Plant crops have been genetically engineered to be disease resistant or to produce bigger fruits.

Current uses of genetic engineering

Production of insulin

Diabetes is a disorder in which the body's blood glucose levels can get too high. It can be treated by injecting insulin. The extra insulin allows the glucose to be taken up from the blood by the liver and other tissues so that blood glucose levels stay normal.

Bacterial cells have been genetically modified to produce human insulin and other substances.

Genetically modified crops

Current genetically modified (GM) crops include those that are resistant to insect pest attack - reducing the need for pesticides - and herbicide resistant crops that allow the use of herbicides in fields to kill weeds. Both produce increased crop yields.

Golden rice

Scientists have added a gene to rice that makes it produce beta-carotene. This changes the colour of the rice to a golden colour. Beta carotene is needed by humans in order to make vitamin A - which is essential for good vision.

The advantage of golden rice is that it can be used in areas where vitamin A deficiency is common, so it can help prevent blindness. However, golden rice is sometimes not being grown commercially due to fears associated with genetically modified crops.

Resistance to ringspot disease

Resistance to diseases could be introduced into susceptible crops using genetic engineering. Not only can this protect the crop, it can also safeguard farmers' livelihoods. An example is genetically engineered papaya plants in Hawaii, which are resistant to papaya ringspot virus.

Future uses - altering the human genome

In the future researchers are hoping to use genetic engineering to be able to overcome some inherited disorders, such as cystic fibrosis and Huntington's disease amongst others.

Potential issues with genetic modification

There are ethical issues involved in genetic modification, as well as concerns about the possible health and environmental risks of genetically modified food.

Concerns about genetically engineering crops include:

• Could inserted genes spread to non-GM plants in the wild?
• Could GM crops harm humans and animals that eat them?
• Could there be allergic reactions to products of the new genes in food?
• Could farmers be forced to buy expensive genetically engineered seed, when they have traditionally kept some seed to plant the following year?
• Moral concerns about modifying genomes - some people believe that it is ethically wrong to create new plant life forms, or to move genes between different species.

For better understanding of these concerns, there is a need for long term studies to check for adverse reactions in both humans and the environment.