Restriction fragment length polymorphism or RFLP analysis is used to identify a change in the genetic sequence that occurs at a site where a restriction enzyme cuts. RFLPs can be used to trace inhertitance patterns, identify specific mutations, and for other molecular genetic techniques.
           Restriction enzymes are proteins isolated from bacteria that recognize specific short sequences of DNA and cut the DNA at those sites. The normal function of these enzymes in bacteria is to protect the organism by attacking foreign DNA, such as viruses.

The red triangles indicate where the enzyme cuts the DNA.

           The restriction enzyme is added to the DNA being analyzed and incubated for several hours, allowing the restriction enzyme to cut at its recognition sites. The DNA is then run through a gel, which separates the DNA fragments according to size. You can then visualize the size of the DNA fragments and assess whether or not the DNA was cut by the enzyme.
Gel with an uncut and cut samples of DNA. Note that the sizes of the cut DNA fragments add up to the size of the uncut DNA.