What type of enzymes are used during the first stage of Strand Displacement Amplification (SDA)?

During the first stage of Strand Displacement Amplification (SDA), the key enzymes involved are DNA polymerases. These enzymes are critical because they catalyze the synthesis of new DNA strands by adding nucleotides complementary to the template strand. In SDA, the process begins with an initiator oligonucleotide that hybridizes to the target DNA, leading to the synthesis of a new strand that displaces the original strand and creates a single-stranded template for further amplification.

Restriction enzymes are not used in this initial stage, as their primary role is to cut DNA at specific sequences, which does not directly contribute to the amplification process itself. Ligases are involved in joining DNA fragments together, typically in processes where DNA molecules have been fragmented or need to be connected, such as in cloning or DNA repair. Reverse transcriptases are specialized enzymes used to convert RNA into DNA, relevant in applications such as quantitative PCR for RNA targets but are not a key component of SDA's amplification steps.

Understanding the role of DNA polymerases in SDA helps clarify their significance in the amplification process, especially in single-strand displacement mechanisms, where they ensure the ongoing replication of DNA molecules.