Nested polymerase reaction - why to do this nested PCR? (Nov/11/2006 )

During nested PCR, first reaction will be done by one set of primersfollowed by nrxt reaction with second set of primers. why to use 2 sets of primers? instead, Can’t we perform the reaction derectly with second set of primers? please help me.

Yes, you can. The purpose of the nested primers is to dramatically increase the specificity of the reaction. The first set amplifies perhaps several pieces of DNA from the template (perhaps not very well). The second set will amplify, from these several pieces, only the one you have designed the primers for. As you probably are aware, semi-nested PCR, with one primer the same is also quite effective.