Genetic engineering modifies the genome of an organism by introducing a gene from another organism to give a desired characteristic. Genes from the chromosomes of humans and other organisms can be 'cut out' and transferred to the cells of other organisms.
Plant crops have been genetically engineered to be resistant to diseases or to produce bigger, better fruits. Crops that have had their genes modified in this way are called genetically modified (GM) crops. Some GM crops are resistant to insect attack or to herbicides, and GM crops generally show increased yields. Bacterial cells have been genetically engineered to produce useful substances such as human insulin, which is used to treat diabetes. Medical research is also exploring genetic modification to overcome some inherited disorders.
There are potential benefits and risks, and some people have objections. Concerns about GM crops include the effect on populations of wild flowers and insects. Some people feel the effects of eating GM crops on human health have not been fully explored.
(Higher tier only) The main steps are: enzymes are used to isolate the required gene; the gene is inserted into a vector, usually a bacterial plasmid or a virus; the vector inserts 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.
