What is the function of the polymerase chain reaction in genetic engineering?

Polymerase chain reaction (PCR) is a common laboratory technique used to make many copies of a particular region of DNA. Typically, the goal of PCR is to make enough of the target DNA region that it can be analyzed or used in some other way. For instance, DNA amplified by PCR may be sent for sequencing, visualized by gel electrophoresis, or cloned into a plasmid for further experiments. Polymerase chain reaction is used in many areas of biology and medicine, including molecular biology research, medical diagnostics, and even some branches of ecology.