The Case of the Druid Dracula

By Peggy Brickman

Abstract

This case is based on a lurid crime featured on the BBC program Crimewatch in December 2001 that was solved thanks to forensic DNA analysis. Students learn how the structure of DNA and the mechanism used by cells to duplicate DNA were critical to the forensic analysis. They then determine the statistical validity of the forensic data in the same way a prosecutor would prepare the case for a courtroom. Written for an introductory biology course of 300+ students, the teaching notes for the case describe how students work in permanent small groups in a lecture hall setting to collaboratively solve the case in class.

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Date Posted

06/27/2006

Overview

Objectives

Understand the similarities and differences in the DNA of humans and how those differences can be exploited for forensic identification.
Understand the structure of DNA and how hydrogen bonds between the nucleotide bases dictate the complementary nature of the double helix. Students will be able to predict the nucleotide sequence of one strand of DNA in a double helix if given its complementary strand.
Describe the technique of polymerase chain reaction (PCR) and relate it to the normal cellular process of DNA replication. Students will be able to predict the sequence of PCR primers that would amplify just one short stretch of DNA out of an entire genome.
Understand how short tandem repeats (STRs) within human chromosomes can be used to generate fingerprints and how to interpret these fingerprints to match the DNA to a specific person.
Use statistical prevalence of STRs to determine the probability that someone else at random in the population could have DNA that matched a sample found at a crime scene.

Keywords

DNA fingerprinting; polymerase chain reaction; PCR; DNA replication; short tandem repeats; STR; amelogenin; AMELX; restriction fragment length polymorphism; RFLP; murder case; criminal investigation; forensic investigation; Wales

Subject Headings

Biology (General)

Forensic Science

Molecular Biology

EDUCATIONAL LEVEL

Undergraduate lower division

FORMAT

PDF

TOPICAL AREAS

N/A

LANGUAGE

English

TYPE/METHODS

Interrupted

Teaching Notes & Answer Key

Teaching Notes

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Answer Key

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