Which technique is used to amplify specific segments of DNA?

• A. Gel electrophoresis
• B. Polymerase chain reaction (PCR)
• C. CRISPR-Cas9
• D. Gene cloning

Answer: (B)

The technique that is employed to amplify specific segments of DNA is the Polymerase Chain Reaction (PCR). PCR is a powerful and widely used method that enables the selective replication of a targeted DNA sequence, allowing researchers to produce millions of copies of a specific segment in a relatively short period.

The process involves repeated cycles of denaturation, annealing, and extension, using heat-stable DNA polymerase, primers specific to the target sequence, and temperature variations to facilitate the different stages of amplification. This ability to amplify DNA makes PCR an essential tool in various applications, including genetic testing, forensic analysis, and cloning.

Gel electrophoresis, while important in the analysis and separation of DNA fragments, does not amplify DNA. On the other hand, CRISPR-Cas9 is a revolutionary gene-editing technology that allows for precise modifications of DNA but does not serve as an amplification method. Gene cloning involves the insertion of DNA fragments into vectors for replication within host organisms, but again, it is not primarily an amplification technique like PCR.