HDA amplifies target sequences using two sequence specific primers flanking the fragment to be amplified and a mixture of enzymes for DNA strand separation and polymerization. In the first step of the HDA reaction, the helicase enzyme loads on to the template and traverses along the target DNA, disrupting the hydrogen bonds linking the two strands. Exposure of the single-stranded target region by helicase allows primers to anneal. The DNA polymerase then extends the 3’ ends of each primer using free deoxynucleotides (dNTPs) to produce two DNA replicates. The two replicated DNAs independently enter the next cycle of HDA, resulting in exponential amplification of the target sequence.