- A useful gene is 'cut' from one organism's chromosomes using enzymes
- Enzymes are then used to cut another organism's chromosome and then to insert the useful gene
- Scientists use this method for lots of things e.g. the human insulin gene can be inserted into bacteria to produce human insulin
Genetically modified (GM) plants have been developed to be resistant to viruses and herbicides
Genes can also be inserted into animals so they have more useful characteristics e.g. sheep can be modified so they produce drugs in their milk that can be used to treat human diseases.