Which technique is used to produce many copies of a DNA fragment quickly?

Which technique is used to produce many copies of a DNA fragment quickly?

• A. Sanger sequencing
• B. PCR
• C. Gel electrophoresis
• D. Restriction digest

Answer: (B)

PCR rapidly amplifies a targeted DNA fragment by cycling temperatures and using two primers that bracket the region to be copied. In each cycle, the DNA is heated to separate the strands, primers attach to the ends of the target sequence, and a DNA polymerase extends new strands, copying the template. Repeating these cycles many times yields exponential amplification, producing millions of copies from a tiny starting amount. This relies on a thermostable polymerase, primers, nucleotides, and a DNA template. It’s aimed at making copies, unlike Sanger sequencing, which determines sequence; gel electrophoresis, which separates fragments by size; or restriction digestion, which cuts DNA at specific sites without increasing copy number. PCR is valued for speed and sensitivity in applications like diagnostics, cloning, and forensic analysis.

PCR rapidly amplifies a targeted DNA fragment by cycling temperatures and using two primers that bracket the region to be copied. In each cycle, the DNA is heated to separate the strands, primers attach to the ends of the target sequence, and a DNA polymerase extends new strands, copying the template. Repeating these cycles many times yields exponential amplification, producing millions of copies from a tiny starting amount. This relies on a thermostable polymerase, primers, nucleotides, and a DNA template. It’s aimed at making copies, unlike Sanger sequencing, which determines sequence; gel electrophoresis, which separates fragments by size; or restriction digestion, which cuts DNA at specific sites without increasing copy number. PCR is valued for speed and sensitivity in applications like diagnostics, cloning, and forensic analysis.