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Genetic engineering

Genetic engineering

  • Scientists can now remove a gene from one organism and insert it into the DNA of another. This is called genetic engineering.
  • This technique produces a genetically modified organism.

Benefits of genetic engineering

  1. Reducing vitamin A deficiency
    1. Beta-carotene is used by our bodies to make vitamin A. Vitamin A deficiency is a big problem in parts of south Asia and Africa. Many children go blind due to this deficiency.
    2. Golden rice is a variety of GM rice which contains two genes from other organisms which together enable the rice to produce beta-carotene.
    3. Growing golden rice in these places will mean the people will eat them and fewer people will suffer from vitamin A deficiency.
  2. Producing human insulin
    1. The human insulin gene can be inserted into bacteria to produce human insulin (see later).
    2. This means, as bacteria reproduce quickly, a lot of human insulin can be produced quickly and cheaply to treat diabetes.
  3. Increasing crop yield
    1. GM crops have had their genes modified to make them resistant to herbicides, for example.
    2. Fields of these crops can be sprayed with herbicide and all the plants except the GM crop are killed. This increases the yield of the crop as there is less competition from other plants.

Controversial

  • Some people think GM crops will affect biodiversity – affecting the number of wildlife that usually lives in and around crops.
  • Not everyone thinks GM crops are safe. Some people think people may develop allergies to the food, but there is probably no increased risk than eating normal foods.
  • Another concern is that transplanted genes may get out into the natural environment. An example is herbicide resistance being picked up by weeds creating a new superweed variety.

Genetic engineering of human insulin

  • Scientists have been able to insert the gene for human insulin into bacterial plasmid DNA.
  • The production of human insulin by GM bacteria has many advantages. Insulin used to be extracted from dead pigs and cattle but now GM bacteria can be used with vegans.
  • Another advantage is that the production of insulin is not affected by animal diseases or the numbers of animals killed for meat.
  • Insulin can be made in vast quantities by using fermenters and can be made more cheaply.
  • However, one disadvantage is that as bacteria produce the insulin slightly differently there are small differences which means it does not suit everyone.

Genetically modifying bacteria to make human insulin

  1. To make insulin, Scientists first have to use a cutting enzyme to cut the insulin
    gene out of a human chromosome.
  2. In bacteria, plasmids are removed and isolated.
  3. A restriction enzyme is used to cut open the plasmids and the human insulin genes are then inserted (DNA ligase enzyme).
  4. The genetic engineers encourage the bacteria to adopt the genetically modified plasmids. Bacteria who adopt this GM plasmid are then multiplied.

By culturing the bacteria a limitless supply of insulin can be produced.