What is DNA Fingerprinting? Case of the Bloody Micropipettor- Student Handout
Late one evening last week the police received a call about a murder in the laboratory of the biotech company GeneSmart. When the police arrived at the company headquarters the police noted that the point of entry had been through the glass window in the door,, The police also notice a small amount of smeared blood on the glass. Lying face down on the floor next to the lab bench was the body of Mr. Skinner, the research director. Underneath the body, the inspectors found the murder weapon, a bloody micropipettor.
The police apprehended Mr. Runyon and Mr. Bell, two former researchers at GeneSmart. Both suspects denied all knowledge of the murder and willingly provided the police with a blood sample.
The Chief Inspector ordered DNA tests on the victim Mr. Runyon and Mr. Bell and blood from the broken glass. You will analyze the DNA samples from the investigation using agarose gel electrophoresis. Based on your DNA analysis, you will determine who should be included as a suspect in the murder.
Some questions to get you thinking about today's lab:
What is DNA and what does it do?
What are some characteristics or properties of DNA?
How can we take advantage of these properties to help us figure out whose DNA was at the crime scene?
What tricks can we use to see DNA?
• DNA from Mr. Skinner #1, Mr. Runyon #2, Mr. Bell (#3), and broken glass (X)
• 0.8% agarose in TAE
• Tris-acetate/EDTA solution (TAE)
• micropipette and tips
• electrophoresis apparatus
1. Get your electrophoresis apparatus. Make sure the comb is placed closest to the black electrode and that there are stoppers at both ends of the gel space.
2. Pour hot agarose into the gel space until it reaches the top of the gel box. Let the agarose harden, which should take about 10 minutes. Don't touch/move your gel until it's hard. Why not?...