How does DNA cloning help scientists make many copies of a gene?

DNA cloning helps scientists produce many copies of a gene by utilizing the natural replication machinery of living cells. The process involves several key steps:12

• Preparation: Scientists isolate the target gene and cut it into fragments using restriction enzymes, which act as "molecular scissors".3
• Insertion: The gene fragment is spliced into a DNA vector—typically a plasmid or virus—using the enzyme DNA ligase to create a stable recombinant DNA molecule.13
• Transformation: This recombinant molecule is introduced into a host cell, such as a bacterium, through a process called transformation.3
• Amplification: Once inside, the host cell treats the recombinant DNA as its own, replicating it during every round of cell division. As the bacterial colony grows, it produces a large number of genetically identical copies of the inserted gene.13

While often confused with the polymerase chain reaction (PCR), DNA cloning is distinct because it relies on living cells for replication, whereas PCR is an in vitro method that amplifies DNA sequences without cloning them.24