Which enzyme is specifically used in MLPA that is not utilized in regular PCR procedures?

In MLPA (Multiplex Ligation-dependent Probe Amplification), ligase plays a crucial role that is not present in standard PCR procedures. MLPA is designed to detect and quantify specific DNA sequences, and the process relies on the precise ligation of probes that are complementary to the target sequences. The ligase enzyme facilitates the joining of two adjacent probes if they are hybridized to the target DNA. This step is essential for the amplification of the ligated probes during subsequent PCR amplification, enabling the analysis of multiple targets simultaneously.

In regular PCR, the main focus is on the amplification of a target DNA sequence using polymerase, which synthesizes new DNA strands. Unlike MLPA, PCR does not require any ligation step, as it simply amplifies the target without the prior need to join probes together. Therefore, ligase is specifically utilized in MLPA for its unique role in probe ligation, setting it apart from the regular PCR procedure that does not involve this enzymatic function.