Uses of Genetic Engineering

Bacteria and Genetic Engineering

Bacteria are a very common target of genetic engineering. This is because:

• Bacteria are easy to grow
• Bacteria reproduce very rapidly
• Can manufacture complex molecules
• Their genetic material uses the same code as all other organisms
• Their use does not carry the same level of ethical concerns as other more complex life forms
• They possess mobile genetic elements known as plasmids, which provide an easy way to insert foreign genes into a cell.

Figure 1. An electron micrograph of Escherichia coli, a bacterial species commonly used in genetic engineering.

Scientists can, and often do, genetically engineer more complex organisms than bacteria, as, especially in areas such as medical research, the simplicity of bacteria prevents the required data from being gathered. An example is the genetic engineering of rats or pigs to research human genetic conditions. As humans are a very complex organism and a mammalian (eukaryotic) organism, it would be much harder, if not impossible, to gather meaningful and representative data from bacteria that are prokaryotic unicellular organisms.

Use of DNA Ligase and Recombinant DNA in Genetic Engineering

Genetic engineering often involves the use of recombinant DNA, also known as rDNA.

One way rDNA can be produced is by using an enzyme known as DNA Ligase. This enzyme carries out a process known as ligation, the joining of two nucleic acid fragments. The full method to produce rDNA is above the level needed here, but below is a brief outline of the process of inserting a human gene into a bacterial plasmid and then using this plasmid to make bacteria produce the protein.

Types of Genetic Engineering

As previously mentioned, genetic engineering may involve inserting, removing, or modifying individual genes. This is one way in which genetic engineering may be categorised; however, they may also be divided based on the purpose of the genetic engineering and the methods used.

Analytical Genetic Engineering

This field uses computers to model or simulate genetic changes before producing the genetic material in real life. This is also known as in silico genetic modification, as it occurs within a computer's silicon, following the same naming conventions as in vitro and in vivo, meaning in glass and the living body, respectively.

Chemical Genetic Engineering

Chemical genetic engineering focuses on identifying, separating, and classifying different genes to provide sufficient information for their use in applied genetic engineering. This field focuses on genetic mapping, which is the location of each gene in individual chromosomes. Genetic identification develops scientists' understanding of which gene or combination of genes is responsible for what phenotypical trait.

Applied Genetic Engineering

This field puts genetic engineering to practical use, actually carrying out the manipulation of an organism's genetic material via genetic engineering techniques, modifying their phenotype to exhibit traits that we desire.

Uses of Genetic Engineering in Medicine

Genetic engineering has a huge potential to revolutionise human medical treatments. Some of the main uses of genetic engineering include:

• Gene drives
• Hybridomas
• Vaccinations
• Gene therapy
• Xenotransplantation
• Modelling genetic diseases
• Recombinant protein production

The application of genetic engineering techniques in medical research and medicine overall is vast. Some of the examples mentioned are extremely useful for us. Recombinant proteins are proteins created from the expression of recombinant DNA and can be life-saving. Hybridomas are fusions of tumour cells and a lymphocyte, used to produce monoclonal antibodies! Genetic engineering may also be used to modify pathogens' properties, allowing them to be used within vaccines.

By introducing the genetic changes responsible for genetic diseases into animals, the genetic condition may be modelled, allowing for research into the condition without needing human experimental research. Xenotransplantation refers to the transplantation of animal organs into humans, and genetic engineering may be used to increase the success rate of this procedure by limiting the immune challenge foreign organs present. Gene therapy especially holds the biggest potential to revolutionise medicine and the treatment of genetic diseases via gene editing. These techniques directly alter an organism's genome to alleviate diseases with a genetic component, such as the insertion of a functioning lactase gene to alleviate lactose intolerance.

Uses of Genetic Engineering in Agriculture

One of the other main areas of genetic engineering applications is agriculture. By modifying a plant, scientists may cause them to produce additional nutrients that they normally would not. They may also be modified to be resistant to chemicals, such as herbicides or pesticides, allowing these to be applied to enhance crop yields. The addition of insecticidal proteins allows plants to be naturally protected from pests. Similar modifications can also be used to convey resistance to many other pathogens such as bacteria, fungi and viruses.

Genetic engineering in agriculture can also be used to modify natural traits of plants. It can be used to modify traits of existing plant products, such as canola, or produce new compounds. They may also be modified to grow quicker, be stored for longer, and many other factors!

Figure 3. Peanut plants engineered to express Bt toxins to protect against pests.

Advantages and Disadvantages of Genetically Engineered Crops

Some of the most common genetically modified crops grown are soya, maise and rice. The use of genetically modified crops is one of the most common and widely seen examples of genetic engineering, also making it the source of most controversy about genetic modification. Below we outline some of the many advantages and disadvantages of plant GMOs (Genetically modified organisms).

Examples of Genetic Engineering

There are several key examples of genetic engineering applications with which you need to familiarise yourself:

• Human insulin production
• Herbicide resistance in crop plants
• Insecticidal proteins in crop plants
• New vitamin production by plants

Genetic Engineering and Human Insulin Production

Human insulin was initially extracted from animal pancreas and is now mainly produced by yeasts and bacteria. Bacteria and yeast are made to produce insulin via a process similar to that described above. The human gene was isolated, then inserted into a plasmid using DNA ligase, following sticky end creation via restriction enzymes. The plasmid was then inserted into bacteria or yeast, which are then grown in large fermenters, with the produced insulin being extracted from it.

Herbicide Resistance and Genetic Engineering

As described in the genetic engineering and agriculture section above, crop plants may be modified to possess resistance to herbicidal chemicals. This allows broad-spectrum herbicides to be sprayed onto fields, removing non-modified plants and limiting competition for resources, maximising yield.

Insect Resistance and Genetic Engineering

By inserting genes for insecticidal proteins, resistance to insect pests can be conveyed to a plant. One example is the insertion of Bt toxins into peanut plants to protect them from lesser cornstalk borer larvae. These are crystalline proteins which exhibit insecticidal action against an array of insects and nematodes.

Genetic Engineering and Plant Vitamins

Genetic engineering may be used to make crops possess vitamins that they otherwise would not. A key example of this is golden rice. This is rice modified to produce the pigment beta-carotene. This not only gives the rice its namesake golden colour but is metabolised to vitamin A within the body. Growth of this rice crop in place of regular rice aids with alleviating vitamin A deficiency in areas where rice is a staple, such as parts of Africa and South Asia.