PCR-based Crime Scene Investigations in the High School Classroom


Course:  Forensic Science Workshop

Date:  June 26-28, 2006  

Location:  Oregon State University, ALS 012

Instructors:  Drs. Kirstin Carroll and Kari van Zee

Contact:  Kathy Blaustein

Course Description:

The intent of this curriculum is to guide students through the thought process involved in a laboratory-based scientific investigation. Students will learn about PCR, gel electrophoresis, genotyping, and genotype matching while asking the question "How can a tiny amount of genetic material (DNA) be used to identify one person out of a billion?"

We will pilot the Bio-Rad Explorer Crime Scene Investigator PCR Basics™ Kit in this activity.  The kit is appropriate for students who have little or no experience with molecular biology or PCR, but may also be suitable for more advanced students with an interest in the details of DNA profiling, forensic science, and statistics. Students who have an understanding of the following concepts would fully appreciate the kit:

• The structure of DNA

• Genotypes and genotyping

• Heredity and the passage of genetic information from parents to offspring

• DNA replication and PCR

• Cell structure and the storage of DNA within the nucleus

• Pattern matching and discrimination

Day 1:

Session 1: PCR amplification

Students learn about how a technique called Polymerase Chain Reaction (PCR).  PCR will be used to amplify five DNA samples - one obtained from a hypothetical crime scene and four from hypothetical suspects. 

Session 2: Electrophoresis of PCR Products

After performing PCR, students use electrophoresis to analyze the DNA samples and identify the genotypes using a reference allele ladder. They then match one suspect's DNA sample to the DNA collected at the scene of the crime.

Day 2:

Session 3:  DNA profiling with multi-loci

Following DNA profiling of a single genetic "locus", students can do additional simulation exercises which uses the 13 core loci used in actual forensic casework. This simple exercise demonstrates the concept of increasing power of discrimination with increasing numbers of loci typed, and illustrates how even siblings can be discretely identified by DNA profiling. Each student team will generate their own set of genotypes, collect and record data on a worksheet, and perform simple statistical calculations.

Session 4:  Lab tour – Jill Townzen: Studying Mosquitoes with PCR-based Techniques

Day 3:

Session 1: Forensics in Real-Life 8:00-1:00

A visit to the Portland Metro Forensic Laboratory.

Course Readings:  These PDF files can be accessed by clicking on the title.  They require Adobe Acrobat Reader to view them.  Download a free copy of Acrobat Reader.  The manuals have been reproduced in their entirety with the permission of the Bio-Rad company, www.explorer.bio-rad.com/   Copies of these pages will be provided for students in the SEPS forensics workshop. June 2006.

  1. Crime Scene Investigator PCR Basics Kit™, Biotechnology Explorer, Instruction Manual, Rev B - Read pp.6-14 and 27-29.

  2. PV92 PCR Informatics Kit™, Biotechnology Explorer, Instruction Manual, Rev C - Read pp. 3-11 and 36-38.

Classroom Activities: 

  1. DNA Typing with Candy

Useful Links

The Human Genome Project DNA Forensics web site - A wealth of information about the project, including descriptions of the research and education components and free resources (books, posters, downloadable PDFs)

Your Genes, Your Choices - describes the Human Genome Project, the science behind it, and the ethical, legal, and social issues that are raised by the project

See Picture Highlights!

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