In this post, in studying the molecular virology,
I would be talking about the

Analysis of viral genome

the analysis of viral genome,
• Agarose gels
• Restriction analysis
• Sequencing
• Southern blot
• Northern blog
• PCR/ RT- RCP

is used. one by one, I will explain to you how do they work.


There are many different ways of extracting DNA bands using agarose gels. And using different methods, different yield or purity of the DNA is produced after extraction. In extraction of the DNA, many different enzymes are being used and hence, there may be various impurities which may inhibit downstream reactions if not efficiently removed from the DNA. After the DNA is exctracted, agarose gels could also be used to purify it.

Below are Videos, explaining how the extraction is made and


More detailed videos on how procedures involved in the production of an agarose gel and on running an Agarose Gel






From the extracting DNA bands using agarose gels, protein sequencing could be used to predict the amino acid sequence of a protein, indirectly from the mRNA of the organism. From there, the restriction enzymes are used to cut the DNA sequence into smaller pieces for an easier deduction of the amino acids sequence. It is done by isolating the mRNA coding for the protein and replicate a certain yield of the DNA, using PCR(polymerase chain reaction).

Next, is the Southern blot. It is a method used to check for the presence of a DNA sequence in a DNA sample combining agarose gel electrophoresis for size separation of DNA and transferring the separated DNA to a filter membrane for probe hybridization. (Where fragment of either DNA or RNA of certain length is used to detect the presence of nucleotide sequences in the sample that are complementary to the sequence in the probe.)

The method for the northern blot is similar to the Southern blot but RNA rather than DNA is analyzed in the northern blot.

Below are 2 videos on southern and northern blot.


Southern blot


Northern blot


Then is the polymerase chain reaction (PCR). It is steps repeated 20 to 30 times to clone copies of DNA. For more information on the procedure, please view the videos below.



Lastly is the reverse transcriptase PCR (RT-PCR) is a method used to convert the RNA back to DNA called cDNA(complementary DNA) As RNA is single stranded, it is fragile and unstable. Therefore, by using the enzymes reverse transcriptase, the double strand form of the cDNA is produced. Then, it goes on to the normal PCR cycle to replicate more of the DNA.

For more information, do go to this website to know more about RT-PCR




And, for a bit for humor, let’s watch this!
The PCR song.




Thanks! signing off, Yanling