What is genetic engineering?

Natural selection and genetic modification · Genetic engineering · note 1 of 3

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What is genetic engineering?Spec 4.10

In short

Genetic engineering is a process that modifies the genome of an organism to introduce desirable characteristics. Usually a gene is taken from one organism and inserted into an organism of a different species, making a genetically modified (GM) organism that can make the protein the gene codes for. For example, bacteria given the human insulin gene make insulin.

Genetic engineering is a process which involves modifying the genome of an organism to introduce desirable characteristics.

Usually a gene for the characteristic is taken from one organism and inserted into another organism of a different species. The organism produced is called a genetically modified (GM) organism. It can now make the protein coded for by the new gene.

Examples of genetic engineering
Organism	Gene inserted	Desirable characteristic
Bacteria	Human gene for insulin	Bacteria make human insulin, to treat diabetes
Crop plants	Gene for resistance to insect pests	Plants are not damaged by the pest

Common mistake:

Genetic engineering is not the same as selective breeding. Selective breeding uses the genes already in a species; genetic engineering changes the genome directly.

Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026

Frequently asked questions

What is genetic engineering in agriculture?

In agriculture, genetic engineering means inserting a gene from another species into crop plants to give them a desirable characteristic. For example, crop plants can be given a gene for resistance to insect pests, so they are not damaged by the pest. The modified plants are called genetically modified (GM) crops.

How is human insulin made by genetic engineering?

Higher tier The human insulin gene is cut out of human DNA with a restriction enzyme, and a bacterial plasmid is cut with the same enzyme so the sticky ends match. Ligase joins the gene into the plasmid, which is then inserted into bacteria. The bacteria make human insulin, which is used to treat diabetes.

What is the difference between genetic engineering and selective breeding?

Selective breeding uses the genes already in a species, choosing parents with desired characteristics over many generations. Genetic engineering changes the genome directly, usually by inserting a gene from a different species. This makes genetic engineering quicker, and it can give an organism a characteristic coded for by another species' gene.

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