What is the main purpose of the polymerase chain reaction (PCR) in forensic DNA analysis?

What is the main purpose of the polymerase chain reaction (PCR) in forensic DNA analysis?

• A. To degrade DNA samples.
• B. To sequence an entire genome.
• C. To copy a DNA segment outside a living cell.
• D. To separate proteins by size.

Answer: (C)

Copying a DNA segment outside a living cell is what PCR does in forensic DNA analysis. This in vitro amplification lets scientists generate large amounts of a tiny or highly degraded DNA sample, making it possible to obtain a workable DNA profile. In practice, primers flank short, informative regions such as STR loci, so these specific DNA fragments can be amplified efficiently and then analyzed by methods like capillary electrophoresis. Because the amplification occurs in the test tube, the original evidence is preserved while enough DNA is produced for reliable comparison across samples. This approach is not about degrading DNA, sequencing an entire genome, or separating proteins by size—those actions belong to different processes or techniques.

Copying a DNA segment outside a living cell is what PCR does in forensic DNA analysis. This in vitro amplification lets scientists generate large amounts of a tiny or highly degraded DNA sample, making it possible to obtain a workable DNA profile. In practice, primers flank short, informative regions such as STR loci, so these specific DNA fragments can be amplified efficiently and then analyzed by methods like capillary electrophoresis. Because the amplification occurs in the test tube, the original evidence is preserved while enough DNA is produced for reliable comparison across samples. This approach is not about degrading DNA, sequencing an entire genome, or separating proteins by size—those actions belong to different processes or techniques.