Restriction enzymes are enzymes that digest DNAs at specific DNA sequences.
In evolutionary studies, they can be used to determine if a DNA sequence recognized by a restriction enzyme varies between isolates. To digest DNA with a given restriction enzyme, DNA is combined with the enzyme in a buffer that is appropriate for optimal enzyme performance. The ability of the enzyme to digest the DNA is assayed by gel electrophoresis. Procedures vary with the type of DNA sample. In order to get the best digestion activity, the correct buffer and temperature must be used.