Description: Quantitative PCR, also known as qPCR or real-time PCR, is a molecular technique that allows for the simultaneous amplification and quantification of a specific DNA molecule. This methodology is based on the polymerase chain reaction (PCR), which is a process that enables the exponential replication of DNA fragments. The main difference from conventional PCR is that qPCR incorporates a detection system that allows for the measurement of the amplified DNA in real time, as the reaction occurs. This is achieved through the use of fluorescent dyes or specific probes that emit light when they bind to the amplified DNA. The precise quantification capability of qPCR makes it an invaluable tool in various fields of molecular biology, genetics, and medicine. Additionally, its high sensitivity and specificity allow for the detection of even small amounts of DNA, which is crucial in applications such as pathogen detection, gene expression analysis, and genotyping. In summary, quantitative PCR is a fundamental technique that has revolutionized molecular analysis, providing accurate and real-time quantitative data on the presence and amount of DNA in biological samples.
History: Quantitative PCR was developed in the 1990s, with significant advancements in detection technology. The first real-time PCR method was introduced in 1992 by Higuchi et al., using a fluorescent dye called SYBR Green. Subsequently, techniques were improved with the introduction of specific probes, such as TaqMan probes, which allowed for greater specificity and sensitivity in DNA detection.
Uses: Quantitative PCR is used in various applications, including the detection of infectious diseases, gene expression analysis, quantification of DNA in environmental samples, and genotyping in genetic studies. It is also fundamental in biomedical research and the development of personalized therapies.
Examples: A practical example of quantitative PCR is its use in detecting the HIV virus in patients, where viral load is quantified to monitor disease progression. Another example is gene expression analysis in cancer cells, where messenger RNA levels are measured to assess the activity of specific genes.
