Question

List the various ways that one could test for the presence of a pathogen (not the immune response) in a human clinical sample. (Hint: think about the viral genome and central dogma of molecular biology.) ?

Answer 1

Ans. Viral genome can be either DNA or RNA. For testing the presence of a pathogen, we can go for the following methods-

- Analysis of DNA can be done to check for extra DNA sequence in the host genome. For viruses having DNA as genetic material, the presence of a new DNA sequence in western blotting analysis will make us know the presence of pathogen.

- Analysis of RNA through northern blotting technique will enable us to find the presence of a new RNA sequence in the host cell. Either as genetic material of the pathogen or from the transcription of viral DNA in case of virus having DNA as genetic material, a new RNA sequence can be found to be present in the host and detection of such new RNA sequence will give us the idea of presence of foreign pathogen.

- Proteins are the products of gene expression. Either from RNA virus or DNA virus, protein will be synthesized as final product of gene expression. Hence, protein analysis throgh western blotting technique can be adopted to find out the presence of proteins encoded from viral genome.