Biology Students Become DNA Detectives

In IB DP Biology, students considered and connected complex ideas as they learned about how restriction enzymes cleave DNA, how electrophoresis can be used to separate and visualise DNA fragments, and how these techniques can be combined to obtain a DNA fingerprint through a simulation.

 

"One of the most important questions I ask myself before I begin planning a learning unit is ‘How can I make learning relevant? How can I link our content to a global context?’ One of my favourite learning activities of the year involved role-playing and DNA fingerprinting.”

Springs Pacelli, Grade 9 Science, IB ESS, and IB Biology Educator

 

In this activity, our ISP “forensic scientists“ used DNA technology to examine evidence from a historical case involving a man they thought had been wrongly convicted.

Students analysed six distinct samples of plasmid DNA. One sample was gathered from the “crime scene,“ while the remaining five samples, obtained from “suspects,“ underwent digestion with two restriction enzymes. The resulting DNA fragments were segregated by size, and students could observe them through the agarose gels.

 

 

Based on DNA fragment patterns, students could compare the crime scene evidence with the suspects’ DNA samples collected, concluding that “Anderson,“ the suspect under investigation, was innocent.