The Basics of Genetic Engineering and the Methods
Genetic engineering is the manipulation of genetic material, which involves altering, replacing or transferring genetic material. This process is used to impart a characteristic of the original organism or source organism in to the target organism. The purpose of doing so is to either produce a new substance or improve functions or characteristics of an existing organism. This is done through either gene transfers, in which new DNA is placed into an organism’s cell, or genetic therapy, in which normal or genetically altered DNA is placed into cells to replace defective genes. Genetic therapy typically involves genetic disorders resulting in a disease or malfunction harmful to the organism. A whole industry has been built around genetic engineering known as biotechnology.
By studying genes and how alterations affect their functions scientists are able to see how genes function, the effect of genetic mutations, how genetic disorders occur and how to treat them. Genetic engineering is not limited to humans though, scientists also modify plants and animals aiming to make them better in one way or another. Plants and animals are modified to enable them to produce proteins for medical research, to be used in Xenotransplantation (in which an animal can provide replacement organs and tissues for humans without harming the animal), to make them more resistant to disease, to make them overall more productive and for many other purposes.
By studying genes and how alterations affect their functions scientists are able to see how genes function, the effect of genetic mutations, how genetic disorders occur and how to treat them. Genetic engineering is not limited to humans though, scientists also modify plants and animals aiming to make them better in one way or another. Plants and animals are modified to enable them to produce proteins for medical research, to be used in Xenotransplantation (in which an animal can provide replacement organs and tissues for humans without harming the animal), to make them more resistant to disease, to make them overall more productive and for many other purposes.
Three Methods
When working with the process of genetic engineering there are three main methods that can be used: the Plasmid method, the Vector method and the Biolistic method.
Plasmid Method
Figure 1
The plasmid method is typically used when altering microorganisms. The plasmid of a cell, which is a small ring of DNA, is removed from a cell and placed in a container with special restriction enzymes that are able to cut the DNA into recognizable segments. New DNA is then placed within the plasmid using the enzyme which allows the DNA to produce “sticky ends” which allow the new DNA and the original DNA to fuse together. Once the DNA sequences are allowed to fuse together the newly formed plasmid is introduced into a culture of live bacteria which is allowed to grow and reproduce and evolve on its own. Figure 1 shows an example of this process.
The Vector Method
Figure 2
The vector method is similar to the plasmid method except that the altered DNA is entered directly into the genome using viruses. The first steps of the vector method are the same as that of the plasmid method except that the DNA that yields a virus as dangerous is removed, leaving an empty space in which new DNA can be placed. The altered virus is then used to infect the genome allowing it to spread the DNA sequence that way. Figure 2 shows an example of this process.
The Biolistic Method
In the biolistic method pellets of metal coated with altered DNA is fired into plant cells, introducing the DNA sequence throughout the plant. The problem with this method is that the DNA could accidently be fired into a working genome, disrupting how the plant functions and possibly killing it. Figure 3 shows the tool used in the biolistic method.