What is a primer dimer?

A primer dimer is a byproduct that can occur during the polymerase chain reaction (PCR) when two primers anneal to each other instead of to the target DNA sequence. This can lead to the amplification of non-target products, reducing the efficiency and specificity of the PCR reaction. Primer dimers typically manifest as shorter DNA fragments and can interfere with the desired amplification of the target DNA. Proper primer design and optimization can help minimize the formation of primer dimers.