This multipart activity is designed to give students a firm understanding of genetic profiling using short tandem repeats (STRs), which is a process used by forensic labs around the world.

In Part 1 of this activity, students learn the basics of DNA profiling, including the structure and inheritance of STRs. In Part 2, students learn how DNA profiles are compiled with STRs that are typically used in forensic investigations. In Part 3, they work through a case study involving a robbery and build a DNA profile that can be compared to one constructed from a DNA sample left by a suspect at the scene of the crime. Throughout, analysis questions walk students through calculations on allele frequency and probability (using real data from national databases), providing opportunities for formative assessments of students’ understanding of DNA fingerprinting applications.

This activity can be used on its own or could be followed by downloading and unzipping the accompanying case studies in which students apply what they have learned to solve four cases: 1) twins switched at birth, 2) revisiting evidence from a crime for which the accused was sentenced to life in prison, 3) identifying a missing person, and 4) identifying victims of an earthquake.

The “Resource Google Folder” link directs to a Google Drive folder of resource documents in the Google Docs format. Not all downloadable documents for the resource may be available in this format. The Google Drive folder is set as “View Only”; to save a copy of a document in this folder to your Google Drive, open that document, then select File → “Make a copy.” These documents can be copied, modified, and distributed online following the Terms of Use listed in the “Details” section below, including crediting BioInteractive.