What is Gel Electrophoresis?






GEL ELECTROPHORESIS

-It is a laboratory procedure through which DNA fragments are separated. The technique uses an electric current to separate DNA fragments. Small DNA fragments move swiftly towards to positive pole than larger fragments. 


-An agarose gel is used to separate DNA molecules (size varies from several hundred nucleotides to over 10,000 nucleotides). Agar is obtained from red algae (Gracilaria and Gelidium).
 

-The agarose gel is deluged in a tank filled with salt solution (as shown in the diagram below) that conducts electricity.


-DNA fragments are loaded with the help of a pipette into the slots made in the agarose gel. 


-Since the phosphate group attached to the 5 prime end of a nucleotide carries a negative charge – the overall DNA molecule can be considered negative in nature. In the electric current –vely charged DNA moves towards the positive pole.






-Once the fragments are run – they travel a distance inside the gel as per their fragment size. The gel can be taken out from the tank and Ethidium bromide fluorescent dye is used to stain DNA. The dye binds to the DNA double helix and glows when seen under UV light. 


 



The DNA fragment size can be determined using markers (these are readymade DNA fragments prepared in the laboratory in various biotechnology based companies – markers have specific DNA sizes)






 


 
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