The process of agarose gel electrophoresis is the most common method in which DNA molecule is separated and analyzed. This method is commonly used in the field pf biochemistry and molecular biology for the isolation of DNA. This technique also supports the separation and analysis of proteins. A chemical ethidium bromide is used to visualize the DNA molecule. The property of this chemical is that it binds to the DNA bases strongly and makes it visualized.
Process of Gel electrophoresis:-
The process of gel electrophoresis for the separation of DNA molecules takes place in the following manner:-
1) Using the restriction enzymes, DNA molecule is cut into small pieces or fragments.
2) The cut DNA fragments are moved to the wells or pots where agarose gel is already present.
3) The agarose gel along with the DNA fragments is passed through an electric current.
4) The well is equipped with negatively and positively charged electrodes. When electric current is released in the gel, the negative electrode repels the negatively charged DNA fragments and they move to the positive pole of well.
5) Through this method DNA fragments can be isolated according to their size and they can easily be visualized.
Applications of Agarose Gel:-
The main purpose of agarose gel is to isolate and analyze the DNA molecules which are cut by restriction enzymes. These cut pieces of DNA can be used for the cloning purpose to make various plasmids from one fragment. The function of gel electrophoresis is to isolate cut plasmids or vectors from the uncut vectors.
Agarose gel can also be used to separate the RNA or protein molecules from the gel. DNA fragments re separated before Southern blotting and RNA and proteins are separated before the Northern blotting. It also allows the DNA fragments to pass through PCR to make various copies of DNA molecules, so that they can be used in DNA fingerprinting or in any other method. DNA molecules of same size can be isolated through the agarose gel, when the electric current is passed through it.
Quantity and quality of the size of DNA molecule is analyzed by lambda DNA ladder and by observing the absence of streaking of fragments respectively. It means that only those DNA fragments can be observed or isolated which have fluorescent streak in them so that they can be identified.
Advantages and Disadvantages:-
The main benefit of agarose gel technique is that it can be easily processed and the DNA molecule that is used as a sample can also be recovered without any harm to it at the end of the process. Agarose gel does not denature the DNA samples and they stay in their own from.
There is also a disadvantage of gel electrophoresis that it may melt when the electric current is passed through it. Due to this reason there are chances that genetic material can adopt the shapes which are not needed.
Use of Gel Electrophoresis:-
Gel electrophoresis can be used the field of forensics. The process of DNA fingerprinting can be performed using the agarose gel DNA electrophoresis.
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