Gene cloning makes copies of a specific gene. It is not the same as cloning an organism. It is a molecular biology technique used to isolate a gene, insert it into a vector, and propagate it in a host cell. The result is many identical copies of the gene, which can be studied, sequenced, or used to produce a protein.

The process has several steps. The gene is amplified by PCR or cut from a larger DNA molecule with restriction enzymes. It is inserted into a vector, usually a plasmid, using ligase. The vector is introduced into a host cell, often E. coli, by transformation. The host cell multiplies, and the plasmid replicates with it. Cells containing the plasmid are selected, usually with an antibiotic resistance marker. The gene is then isolated from the host cells.

Gene cloning is used to produce insulin, growth hormone, and other therapeutic proteins. It is used to study gene function by expressing the gene in a model organism. It is used to create genetically modified crops and animals. It is a foundational technique of biotechnology.

The technique is not without challenges. Some genes are difficult to clone because they are toxic to the host or unstable. Others require special vectors or host strains. But for most genes, cloning is routine. It is the first step in many experiments.