Variation in living organisms can also be created by genetic engineering, also called genetic modification, or just 'GM'.

Using laboratory techniques scientists can alter the genetic code within the DNA of a living organism. They can add genes from a different species to an organism's DNA

For example, GM can be used to alter the DNA in a bacterium so that it produces insulin. This is a human hormone and valuable to people with diabetes. Bacteria reproduce quickly, so a lot of insulin can be made quickly and used to help people suffering from diabetes.

Ethical questions

Some people are concerned that there may be negative aspects to GM.

For example, there are people that believe GM is unethical and should be banned.

Other people are concerned that there may be unexpected long term problems of using GM, producing changes that could not be reversed. Such changes could create new pathogens or "superweeds" by the GM organisms breeding with other species. This could cause the natural balance of living organisms in the environment to be upset.

Scientists, society and individuals need to think about the advantages and disadvantages of genetic engineering.