How can I reduce non-specific bands in PCR?

1. Appropriately increase the annealing temperature, the non-specific band is the mismatch between the primer and the template at the non-target band, and the higher annealing temperature can reduce the non-specific reaction to a certain extent. When designing the reaction program, the number of main cycles should not be too high, and after multiple cycles, the fidelity of DNase decreases, and non-specific bands are easy to generate.  

2. Use purer and fresh templates for amplification, and pay attention to the appropriate concentration of templates used.  

3. If the specificity of the primer is low, it will lead to the production of non-specific bands, and attention should be paid to this aspect when designing primers, and a relatively diffuse low-brightness band will be produced at 100bp of the gel, which is a primer dimer.  

4. Too high a concentration of Mg2+ will lead to a large number of non-specific amplification.