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Biotechnology is the alteration of living organisms to develop or make products that help us. This is quite a broad definition and so many different organisms or processes are involved. Humans have used biotechnology for thousands of years in agriculture and used selective breeding to produce better foods and medicines. More recent examples of biotechnology include cloning and genetic modification. Biotechnology can help us meet the food demands of our ever increasing population.

Crops directly feed us or animals we keep for food. They are commonly cereals, fruit and vegetables. We can change (or modify) crops in two key ways - selective breeding and genetic modification.

Genetic modification

Scientists can now identify the genes in some species that control some characteristics. These genes can be removed using enzymes and inserted into the genome of other individuals within the same species or those in other species. This is genetic modification (or engineering). The organism that has been modified is called transgenic.

A common example of genetic modification involves the transfer of the glow-in-the-dark gene from jellyfish into mammals such as mice or rabbits. This gene is inserted into the embryo of the mammal so only a small number of cells need to be altered. As the embryo develops, all of its newly grown cells will contain the transferred gene.

We have genetically modified bacteria to contain the human gene for insulin. These bacteria therefore produce human insulin which is used by diabetics to manage their diabetes.

Golden rice is a variety of rice that has been genetically modified to contain beta-carotene which helps people who do not get enough vitamin A in their diet. This deficiency disease kills over half a million children each year. We have also genetically modified soybeans, cotton and corn to also include beta-carotene.

Other crops have been genetically modified to be resistant to insects. A bacterium called Bacillus thuringiensis naturally produces a toxin which kills many insects. The gene responsible for this has been identified, removed and inserted into crop plants.

Other crops have also been genetically modified to be resistant to pesticides. The genes that occurs naturally in some plants will be identified, removed and inserted into crop plants. This means that farmers can spray whole fields with pesticides and kill the pests, not the crops.

It is likely that all crops have been selectively bred to have greater yields.

Selective breeding

For thousands of years farmers have instinctively known to breed together - a big bull and a big cow to have big calves. This is selective breeding. It occurs when animals or plants with a desirable characteristic are selected to breed with each other. Because of inheritance, their offspring are likely to have the desired characteristic. Over generations these characteristics have become enhanced.

All breeds of dog belong to the same species. They were all originally bred from wolves. Dogs have been bred for a variety of reasons including protecting livestock, hunting, providing company and for their different shapes, sizes and colours. They have all been selectively bred for these different characteristics.

Other specific examples include:

1. Friesian cows to produce large volumes of milk and Jersey cows to produce creamy milk
2. Wheat that is resistant to some diseases

Unlike selective breeding, genetic modification is an ethical issue which means some people disagree with it for religious or other personal reasons. Some people believe that the genes might spread to other species.