Gel Electrophoresis Virtual Lab:
DNA Fingerprinting
Purpose: To use gel electrophoresis techniques to create a DNA fingerprint of evidence left at a crime scene. Then
analyze and compare DNA profiles of victim and suspect DNA to determine whether a link exists to the crime scene
evidence.
Pre lab Question: Explain how comparing DNA Fingerprints can help identify a person who has committed a crime.
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Explore:
Explore the lab – click on each of the materials to be used in the simulation
Procedure: Briefly describe each of the steps for gel electrophoresis.
1. _Answer the pre lab question in the lines provided above. ________________________________________
_______________________________________________________________________________________
2. _______________________________________________________________________________________
_______________________________________________________________________________________
3. _______________________________________________________________________________________
_______________________________________________________________________________________
4. _______________________________________________________________________________________
_______________________________________________________________________________________
5. _______________________________________________________________________________________
_______________________________________________________________________________________
6. _______________________________________________________________________________________
_______________________________________________________________________________________
7. _______________________________________________________________________________________
_______________________________________________________________________________________
8. _______________________________________________________________________________________
_______________________________________________________________________________________
9. _______________________________________________________________________________________
_______________________________________________________________________________________
10. _______________________________________________________________________________________
_______________________________________________________________________________________
11. _______________________________________________________________________________________
_______________________________________________________________________________________
12. _______________________________________________________________________________________
_______________________________________________________________________________________
BAND MARKER DNA VICTIM DNA
(bp)
(bp)
1
23130
2
9416
3
6557
4
4361
5
2322
6
2027
7
8
9
10
SUSPECT 1
DNA (bp)
SUSPECT 2
DNA (bp)
EVIDENCE
DNA (bp)
POST LAB QUESTIONS:
1. EVALUATE. Does the DNA found on the hair match suspect 1 or suspect 2? __________________________
2. ANALYZE. What do the series of bands on the gel represent? _____________________________________
3. IDENTIFY CAUSE. Why is the largest DNA fragment band closest to the well in which it was placed?
_______________________________________________________________________________________
4. INFER. What is true of the DNA fragment band closest to the positive end of the gel __________________
_______________________________________________________________________________________
5. INFER. Based on how the power supply is connected, what electrical charge does DNA have? __________
6. PREDICT. What would happen if the electrodes were plugged into the wrong outlets? ________________
_______________________________________________________________________________________
7. APPLY. Why is DNA Fingerprinting more conclusive when proving a person’s innocence rather than their guilt?
_______________________________________________________________________________________
_______________________________________________________________________________________