What are the applications of restriction enzymes?

Restriction enzymes are a type of enzyme that cleaves DNA into fragments at or near specific recognition sites known as restriction sites. They are widely used in molecular biology to manipulate DNA for various scientific applications including but not limited to: 

Genetic Engineering - Researchers use restriction enzymes to manipulate the genetic composition of organisms and seamlessly introduce sequences of interest in the host’s genome. This enables the host organism to produce the desired gene product. This concept finds extensive application in biotechnology, particularly with regards to producing antibiotics, enzymes, antibodies, and a range of essential secondary metabolites.

Gene Sequencing - Gene sequencing involves the fragmentation of a large DNA molecule using restriction enzymes. A DNA sequencer is then used to analyze the resulting fragments and obtain the nucleotide sequence.

DNA Mapping - DNA mapping using restriction enzymes is often used to obtain structural information of DNA fragments. In this technique, also known as restriction mapping, DNA fragments of various sizes are produced by subjecting the DNA to digestion by a series of restriction enzymes. Agarose gel electrophoresis is then used to separate the resultant fragments, allowing researchers to estimate the distance between the restriction enzyme sites and determine the structure of an unknown DNA fragment.

Gene Cloning - Restriction enzymes are instrumental in gene cloning, the process of making multiple copies of a specific gene. In this process, a gene is first inserted into the plasmid. Restriction enzymes are then used to cut the plasmid, resulting in single –stranded overhangs. In this process, a single DNA molecule is formed by ligating two DNA molecules with the help of DNA ligase. 

Gene expression and mutation studies and examination of population polymorphism are other applications of restriction enzymes.