Plasmid vs cDNA amplification by PCR - (Mar/29/2012 )
why is it easier to amplify plasmid DNA than it is to amplify cDNA?
standard primers and, therefore, well defined conditions.
And when talking about the same sequence in plasmid and in cDNA, plasmid DNA contains only huge number of copies of relatively small, not-complex stable molecule, but cDNA is a mix of all transcriptome of cells, RNA maybe degraded before RT and thus contain incomplete molecules, cDNA may degrade too, plus contaminants from RT blocking PCR.
And I'm sure I left something out.