Nested polymerase chain reaction (Nested PCR) is a modification of polymerase chain reaction intended to reduce non-specific binding in products due to the amplification of unexpected primer binding sites.
I understand that there are two steps and one of those steps involves a non-specific primer followed by a specific primer...
But this does not seem to have sense. What is the purpose of running a non-specific PCR just to hit it with a specific primer afterwards?
What do we gain when doing a nested PCR?
Practical example: We are planning on sequencing human skin microbiome. Would the ratios of different bacterial species differ if we would use the nested PCR products for sequencing, as compared to standard PCR?