DNA Profiling Activity

Topic
Resource Type
Description
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.
Student Learning Targets
- Interpret electrophoresis results by distinguishing DNA fragments by length and determining whether individuals are homozygous or heterozygous at different STR loci.
- Calculate allele frequencies and the probability of generating a match, at random, at one or more loci using allele frequency data.
Estimated Time
Key Terms
allele, DNA profile, electrophoresis, flanking sequence, genetic fingerprint, heterozygote, homozygote, locus, polymerase chain reaction (PCR), primer, repeat unit, short tandem repeat (STR)
Primary Literature
Hill, Carolyn R., David L. Duewer, Margaret C. Kline, Michael D. Coble, and John M. Butler. “U.S. population data for 29 autosomal STR loci.” Forensic Science International: Genetics 7, 3 (2013): e82–e83. http://dx.doi.org/10.1016/j.fsigen.2012.12.004.
Jeffreys, Alec J. “Genetic Fingerprinting.” Nature Medicine 11,10 (2005): 1035–1039. https://doi.org/10.1038/nm1005-1035.
Terms of Use
Please see the Terms of Use for information on how this resource can be used.
Version History
NGSS (2013)
HS-LS3-1, HS-LS3-3; SEP2, SEP4, SEP5
AP Biology (2019)
IST-1.I, IST-1.K, IST-1.P, SYI-3.C, EVO-1.K; SP2, SP4, SP5
IB Biology (2016)
2.7, 3.5, 7.1, B.5
Common Core (2010)
ELA.RST.9–12.4, ELA.RST.9–12.7, ELA.WHST.9–12.1
Math.N-Q.1, Math.A-CED.1, Math.A-REI.3, Math.S-IC.1; MP1, MP3, MP4
Vision and Change (2009)
CC3, CC5; DP1, DP2, DP3, DP6