If the concentration of Mg2+ is too low during PCR, what is the expected outcome?

During polymerase chain reaction (PCR), magnesium ions (Mg2+) serve as a crucial cofactor for DNA polymerase, the enzyme responsible for synthesizing new DNA strands. If the concentration of Mg2+ is too low, the enzyme's activity is greatly reduced, leading to inadequate DNA synthesis.

Low levels of Mg2+ can result in the polymerase being unable to properly bind to the template DNA and facilitate the addition of nucleotides. Consequently, this diminished enzymatic activity leads to ineffective amplification, yielding little to no PCR product.

In contrast, higher concentrations of Mg2+ can enhance the activity of the polymerase, potentially allowing optimal production of the desired DNA fragments. However, if Mg2+ is not at the correct level, the enzyme simply cannot function properly, directly impacting the overall efficiency of the PCR process. Thus, with insufficient Mg2+, the expected outcome is indeed very minimal or no PCR product.