miniPCR bio™ Electrophoresis Forensics Lab. Wrongfully Convicted? Instructor's and Student's Guide
Version: 1.1 - Release February 2022 - © 2022 by miniPCR bio™
Student's Guide
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Critical thinking
5. Gel electrophoresis was used to separate
fragments for a single STR location, which we
will call "STR 1" for simplicity.
A. Every person has two alleles for STR 1.
Which sample(s) comes from a person
where the two alleles are different from
each other? Explain how you can tell.
DIRECTION
OF MIGRATION
400 bp
300 bp
200 bp
100 bp
LADDER SAMPLE
1
SAMPLE
2
SAMPLE
3
SAMPLE
4
B. Which sample(s) comes from a person where the two alleles are the same? Explain
how you can tell.
C. Do any of the samples come from people who have the same genotype? Explain how
you can tell.
D. Do any of the samples have alleles that are the same? If so, circle them on the gel and
explain how you can tell.
