I want to amplify a 224 bp product from genomic DNA, isolated from blood.
At the beginning of my experiments it worked well but after some PCRs I
got a smear, also in the negative. Sometimes I have samples that work
well but in the next PCR they don't work anymore. I already bought new
primers, changed the MgCl2 concentration, added DMSO, changed the method
of DNA isolation but without results.
Could anybody help me please?
Peggy De Clercq