1. DNA Fingerprinting
Gel Electrophoresis

2. Making a DNA Fingerprint
Obtain a DNA sample
Cut the DNA into fragments
How can DNA be cut?
Put the fragments into the end of a rectangular plate filled with gel
Pass an electric current through the gel

3. What happens to the DNA?
The electric current causes the DNA to move through the gel
Smaller pieces move more easily, so they move further
Each fragment of DNA stops at a different point
The DNA is stained so that it is visible

9. The Fingerprint
The pattern of dark bands is called the DNA fingerprint
Each person has a unique DNA fingerprint
Each band in the DNA can be matched with an individual’s mother or father

10. Uses for DNA Fingerprints
Link a suspect to a crime
Confirm family relationships
Identify the remains of a deceased individual
Detecting genes that cause some disorders (Huntington’s disease and sickle cell anemia)