Trouble shooting: Multiple products

Touchdown PCR may be needed.
o “Touchdown” PCR significantly improves the specificity of many PCR reactions in various applications. Touchdown PCR involves using an annealing/extension temperature that is higher than the TM of the primers during the initial PCR cycles. The annealing/ extension temperature is then reduced to the primer TM for the remaining PCR cycles. The change can be performed in a single step or in increments over several cycles.