Which of the following methods PCR is called Quantitative PCR
**Core Concept:**
PCR (Polymerase Chain Reaction) is a molecular technique used in biotechnology and medicine to amplify a small amount of DNA or RNA to produce a large quantity of identical copies for further analysis or sequencing. Quantitative PCR (qPCR) is a variant of PCR that measures the amount of amplified product in real-time, enabling quantification of the initial template quantity.
**Why the Correct Answer is Right:**
PCR is a technique used to amplify DNA or RNA. Quantitative PCR (qPCR) is a variant of PCR that adds a fluorescent probe to the reaction mix. As the probe binds to the amplified product, the fluorescent signal increases, allowing for real-time monitoring of the reaction progress and quantification of the initial template quantity.
**Why Each Wrong Option is Incorrect:**
A. **False Positive (FP):** False positives occur when the amplification signal is generated due to non-specific binding or other factors, not reflecting the actual template quantity.
B. **False Negative (FN):** False negatives occur when the amplification signal is not generated despite the presence of a template, indicating inadequate amplification.
C. **Increase in Amplification Cycles (IC):** Increase in amplification cycles indicates a lower initial template quantity, but does not specifically quantify it.
D. **Non-Increase in Amplification Cycles (NIC):** Non-increase in amplification cycles indicates a higher initial template quantity, but does not quantify it accurately.
**Clinical Pearl / High-Yield Fact:**
The concept of "Base Pair Equivalents" (BPE) is used in qPCR to standardize the amplification results. BPE represents the number of DNA or RNA molecules in the initial template, allowing for accurate quantification of the initial quantity.
**Correct Answer:**
C. Increase in Amplification Cycles (IC)
Explanation:
In the context of PCR, the increase in amplification cycles corresponds to a lower initial template quantity, which is a feature of quantitative PCR (qPCR). This method is used to determine the initial quantity of the template, allowing for accurate quantification. However, it does not directly quantify the template, and therefore, it is not the correct answer.
In real-time PCR, the BPE (Base Pair Equivalents) method is used to standardize the results based on known quantities of DNA or RNA templates. Using BPE, the results can be accurately compared between different samples and experiments. By using BPE, the results of qPCR can be converted into absolute quantification, allowing for precise determination of the initial quantity of the template.