Gel electrophoresis is used for
(a) cutting of DNA into fragments
(b) separation of DNA fragments according to their size
(c) construction of recombinant DNA by joining with cloning vectors
(d) isolation of DNA molecule
(b) When genomic DNA extracted from any tissue of a plant or animal species is digested with a restriction enzyme, it is cleaved into segments. The segments of different sizes can be separated through gel electrophoresis. Gel electrophoresis involves the movement of fragments from a well created on one edge of the gel. Endonucleases are enzymes that produce internal cuts called cleavage in DNA molecules. A class of endonucleases cleaves DNA only within or near those sites, which have specific base sequences, such endonucleases are known as restriction endonucleases. The selected vector is cut open with a restriction enzyme that has a unique target site located in the sequence where the DNA insert should be integrated to facilitate the selection of recombinant DNA.