variation in the length of a DNA fragment produced by a specific restriction enzyme acting on DNA from different individuals that usually results from a genetic mutation and that may be used as a genetic marker. 
Restricted Fragment Length Polymorphisms are used to identify similar strands of DNA which are then examined to find any differences in strand makeup. The restricting enzymes cut DNA to precise points to produce lengths of DNA strand, which are called restriction sites. Then they are paired with a base to determine ehether they are similar or not. [general 1]
Forensic teams use this method to do crime scene DNA testing. This process allows them to accurately test whether the DNA at the scene of the crime is the same as the one in their database. Another way this is used is to screen for genetic disorders such as sickle cell. Testers are able to see whether a patient has Valine at the sixth position of the beta chain of the hemoglobin molecule instead of Glutamine Acid, which a healthy individual has at this position.
1: Merriam-Webster. "Restriction Fragment Length Polymorphisms (RFLPs)." Merriam-Webster. Merriam-Webster, 2015. Web. 18 Mar. 2015. <http://www.merriam-webster.com/dictionary/restriction%20fragment%20length%20polymorphism>.
2: Campbell. "RFLP Method - Restriction Fragment Length Polymorphism." RFLP Method. Davidson College Department of Biology, 2001. Web. 18 Mar. 2015. <http://www.bio.davidson.edu/courses/genomics/method/rflp.html>.
3: Kimball, John W. "Restriction Fragment Length Polymorphisms (RFLPs)." Restriction Fragment Length Polymorphisms (RFLPs). Taylor Foundation, 1994. Web. 17 Mar. 2015. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/RFLPs.html>.
<ref>tags exist, but no
<references/>tag was found
<ref>tags exist for a group named "general", but no corresponding
<references group="general"/>tag was found.