What potential issue arises when using non-proofreading DNA polymerases with high dNTP concentrations?

Using non-proofreading DNA polymerases with high concentrations of dNTPs can lead to a loss of fidelity during DNA synthesis. Non-proofreading polymerases lack the 3' to 5' exonuclease activity that proofreading polymerases possess. This means they do not have the ability to correct errors that occur during DNA synthesis.

When the dNTP concentration is high, the likelihood of incorporating incorrect nucleotides increases, as these enzymes are less discerning about which nucleotide they insert into the growing DNA strand. The absence of a proofreading mechanism means that mismatched bases can remain in the newly synthesized DNA, ultimately resulting in mutations.

Therefore, the impact of using a non-proofreading polymerase under these conditions is a significant reduction in the accuracy of DNA replication, which is characterized by a loss of fidelity. The other potential issues, such as PCR inhibition, decreased amplification, or delayed annealing, do not directly relate to the role of non-proofreading polymerases and high dNTP concentrations in affecting the accuracy of DNA synthesis in this manner.