What is the significance of amplifying products of previous rounds in Nested PCR?

The amplification of products from previous rounds in Nested PCR significantly contributes to increasing the overall quantity of DNA. Nested PCR is a technique that involves two sets of primers; the first set amplifies a target region, and the second set, which is specific to a region within the first amplicon, further amplifies that product. This two-step amplification process leads to a much higher yield of the desired target sequence, enabling researchers to work with lower quantities of starting DNA.

The increase in DNA quantity is crucial for various applications, including detection of low-abundance targets, development of genetic tests, and analysis in situations where the initial sample is scarce. While the other answer options touch on important aspects of PCR, such as minimizing contamination or maintaining sequence integrity, the primary significance of nested PCR's approach is the enhanced amplification it achieves, leading to greater DNA yield. This makes it especially valuable in molecular diagnostics and research where sensitivity and specificity are critical.