I am getting smear in the gel of my pcr of CDNA samples, and to surprice me, I am getting band in GAPDH +ve control but not in my CDNA samples... Also I incorporated 2 plasmids as +ve controls, there also I am getting smear....
I made single PCR mastermix for GAPDH and my CDNA samples(except for primers and templet, i.e. these two components added separately.)
So what can be reason for the smears in my pcr of CDNA samples?