A process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.
In genetic engineering, genes from the chromosomes of humans and other organisms can be 'cut out' and transferred to cells of other organisms.
Plant crops have been genetically engineered to be resistant to diseases or to produce bigger, better fruits.
Bacterial cells have been genetically engineered to produce useful substances such as human insulin to treat diabetes.
Crops that have had their genes modified in this way are called genetically modified (GM) crops. GM crops include ones that are resistant to insect attack or to herbicides. GM crops generally show increased yields.
Benefits, risks and objections
Genetic engineering in agriculture and medicine
Potential benefits
Potential risks and objections
Agriculture
Increased yields; resistance to insects, herbicides or disease; bigger, better fruits
Effects on populations of wild flowers and insects; some people feel the effects of eating GM crops on human health have not been fully explored
Medicine
Bacteria can make useful substances such as human insulin; research is exploring genetic modification to overcome some inherited disorders
Some people object to altering the genes of organisms, especially humans; long-term effects may not be known
Some people have objections to genetic engineering, even though it has huge potential benefits.
Higher tier
The main steps in genetic engineering
Higher tier
Enzymes are used to isolate the required gene.
The gene is inserted into a vector, usually a bacterial plasmid or a virus.
The vector is used to insert the gene into the required cells.
Genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development, so that they develop with the desired characteristics.
Higher tier
Higher tierTap to enlargeEnzymes isolate the gene, a plasmid (vector) carries it into a bacterium, and the bacteria multiply and make human insulin.
Tap to enlarge