Which technique is used for copying short pieces of DNA and making millions of copies quickly?

The technique used for copying short pieces of DNA and rapidly producing millions of copies is known as Polymerase Chain Reaction (PCR). PCR is a powerful molecular biology method that allows for the amplification of specific DNA segments. It works by utilizing repeated cycles of heating and cooling, which facilitate the denaturation of the DNA double helix, annealing of primers (short sequences that are complementary to the DNA of interest), and extension by DNA polymerase to synthesize new DNA strands.

The efficiency and speed of PCR make it invaluable in various applications such as genetic research, forensic analysis, medical diagnostics, and cloning. The ability to create millions of copies of a specific DNA segment quickly enables scientists and researchers to work with minimal amounts of DNA starting material, making PCR an essential tool in the field of molecular biology.

In contrast, techniques like CRISPR are used for gene editing rather than copying DNA, gel electrophoresis is primarily used for separating DNA fragments based on size for analysis rather than amplification, and DNA sequencing focuses on determining the nucleotide sequence of DNA rather than copying it. Each of these methods serves distinct purposes and does not replicate DNA in the way that PCR does.