Honors Biology
Outbreak Lab
Name____________________________________ Date_____________
DNA profiling is the analysis of DNA fragments to determine whether they come from a particular person,
bacteria or virus. While this lab is being completed, read the section titled DNA Profiling in Chapter 12, pages
242-246, to learn how DNA extraction, gel electrophoresis, and PCR are applied to the field of crime
investigation. Answer the questions below. It will help you complete this lab correctly which is to determine
which suspect is connected to a crime which has provided DNA evidence.
1. How do scientists compare two samples of DNA to see if they come from the same person?
2. What is the purpose using the polymerase chain reaction (PCR) in crime scene investigation?
3. Describe how PCR works.
4. Where does one find repetitive DNA sequences in the human genome?
5. Why can STR’s be used in DNA profiling?
6. Define single nucleotide polymorphism (SNP).
7. Where are SNP’s found in the human genome?
Outbreak Lab:
What is the purpose of this lab investigation?
The Gel:
A gel has been poured and prepared for you in the gel box and is in the electrophoresis chamber. Buffer fills
the chamber and covers the gel. The buffer is blue in color because it has the stain that will stain the DNA
fragment. Before your group loads the gel, remove the comb from the gel.
Load the Gel:
When loading the gel, steady your pipetting hand with your other hand and don’t poke the tip of the gel through
the gel. Carefully pipette the entire sample and load into the gel. Remember to change tips between samples
Load Order is as follows: Alabama Strain, Pennsylvania Strain, and Missouri Strain.
Run the Gel:
Once the gel has been loaded, the teacher will carefully connect the apparatus to the power supply matching red
to red and black to black and after your instructor has checked it, turn it on. Keep checking on your gel until the
front of the dye has moved ¾ of the way down the gel. To stop the gel, turn off the power supply, remove the
gel tray and slide the gel from the staining tray.
Draw a diagram of the gel that was loaded with the samples of viral DNA. Draw the diagram will the wells on
the top and remember, the gel lanes are read from left to right.
As a technician at the CDC, what are you hoping the results of the test will be? Explain.