Gel electrophoresis is a technique used to separate a mixture of digested
DNA fragments. An electrical field is used to move the negatively charged DNA
molecules through porous agarose gel. Fragments of the same size and shape move
at the same speed, and because smaller molecules travel faster then larger molecules,
the mixture is separated into bands, each containing DNA fragments of
the same size.
The amount of exposure the DNA receives to restriction enzymes determines the portion of possible sites that were actually cleaved. Therefore, by applying different exposures to the same DNA sequence, we can measure all possible lengths of DNA fragments, that one can obtain using a particular enzyme. From this information we can attempt to find out where are the sites located in the original molecule. This problem is known as:
