DNA adding tapeSummary
In this CSI activity, students solve a mystery using “DNA” taken from the scene of the crime. This write up describes how to collect a “DNA sample” (student invented DNA sequence on adding machine tape) from the culprit and from each person in the class, then run the DNA on a “gel” that covers the floor of the classroom, a hallway, or gymnasium. Naturally, the CSI aspect can become as elaborate as you wish by including additional “clues” such as fingerprints, a ransom note written in a specific type of ink, cloth fibers, eyewitness accounts and more. Since both DNA fingerprinting and paper chromatography (see Sources for lesson plans) rely on the same principles – separating molecules by size – a crime scene in which there is both a note written in a specific type of water-based ink as well as a DNA sample that may compared to the students’ DNA draws some interesting parallels conceptually between these two CSI techniques.
Objectives
Can explain what restriction enzymes do.
Can explain how gel electrophoresis works.
Can describe DNA fingerprinting methods.
Can discuss some of the considerations in evaluating DNA evidence in a crime.
Vocabulary
DNA replication
DNA polymerase
DNA fingerprinting
Restriction enzyme
Restriction fragment length polymorphisms
Short tandem repeats
Polymerase chain reaction
Gel electrophoresis
