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Science

Reproduction

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Genetic modification

Genetic modification, or GM for short, is not the same as cloning. Although cloning techniques are used in genetic engineering, the two things should not be confused. This table shows some of the differences.

Key differences between cloning and genetic engineering

cloninggenetic engineering
produces exact copiesproduces a unique set of genesgene: The basic unit of genetic material inherited from our parents. A gene is a section of DNA which controls part of a cell's chemistry - particularly protein production.
genes copied within the same speciesgenes can be swapped across species

How it works

Certain enzymes [enzyme: A protein which speeds up chemical reactions. ] can cut pieces of DNA [DNA: The material inside the nucleus of cells, carrying genetic information. DNA stands for Deoxyribonucleic Acid. ] from one organism, and join them into a gap in the DNA of another organism. This means that the new organism with the inserted genes has the genetic information for one or more new characteristics. For example, the organism might produce a useful substance, or be able to carry out a new function. We say that the organism has been genetically modified.

Genetic modification works in animals, plants and microorganisms. For example, new genes can be transferred to crop plants to make GM crops. Some GM crops are resistant to certain herbicides (weed killers) while others are resistant to insect pests.

The animation shows how the method can be used to produce bacteria that make insulin. This is a human hormone and valuable to people with diabetes. Bacteria reproduce quickly, so a lot of insulin can be made quickly.

Problems

Watch

You may wish to view this BBC News item (2005) about some hostility in France towards GM crops.

There are strong arguments for and against genetic modification of crop plants. GM crops generally have increased yields, useful for feeding a growing population. Tobacco plants that glow in the dark when they need watering have even been produced.

However, some people are excited by the almost limitless possibilities of genetic modification, while others believe the process is unethical and should be banned. There are concerns about the effect of GM crops on wild flowers and insects, and whether eating GM food may harm human health.

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