Final answer:
The type of PCR that uses a fluorescent dye to monitor and quantify DNA amplification in real-time is called real-time PCR or quantitative PCR (qPCR). It is especially useful for determining relative changes in gene expression and has many applications in molecular biology.
Step-by-step explanation:
The Polymerase Chain Reaction With Fluorescent Dye
The type of Polymerase Chain Reaction (PCR) that utilizes a fluorescent dye to determine relative changes in gene expression is known as real-time PCR, also referred to as quantitative PCR or qPCR. In this variant of PCR, scientists can monitor the amplification of DNA in real-time using fluorescence, which allows for the quantitation of the original target sequence. This is in contrast to traditional PCR, where the amplification of nucleic acid fragments is observed after the process has been completed.
Real-time PCR is an invaluable tool in molecular biology and has numerous applications, including measuring changes in gene expression levels, detecting genetic diseases, and identifying DNA contaminants in samples. The use of fluorescent dyes, such as in the addition of fluorescent ddNTPs, enables the visualization of DNA amplification as it occurs. By employing specific probes that emit fluorescence upon binding to the target DNA sequence, researchers can quantify the amount of starting material accurately.