Gene Testing Provides Data on Mutations

2 http://www.nlm.nih.gov/medlineplus/genetictestingcounseling.html

Gene Mutations - Genes can be mutated in many ways. The most common gene change involves a single base mismatch placing the wrong base in the DNA. At other times, a single base may be deleted or inserted. And sometimes large pieces of DNA are mistakenly repeated or deleted.

2 http://rex.nci.nih.gov/behindthenews/ugt/genetestingframe.htm