Hello,

I'm doing site directed mutagenesis. So far, I didn't have any issues. For one construct only, I get insertions that are equal to my primer sequences. Sometimes it is 1, sometimes it's 3 insertions, depending on the clone. I know that this can sometimes happen when the transformed bacteria ligate the nicked ends of the plasmid. But in my case, I did an agarose gel extraction of my plasmid before transformation. I cannot really explain where those primer inserts come from. I assume it must happen during PCR? Is there any way to avoid this phenomenon?

Thank you very much.