Modeling Short Tandem Repeat (STR) DNA Fingerprinting Using Standard Playing Cards

In genetics, lab activities can improve the learning process but are typically expensive and require teaching lab facilities. Sometimes, a hands-on in-class activity can help fulfill some of the same learning goals as a traditional lab. For this lesson, I created an activity on DNA fingerprinting where each student has their own unique data. Rather than having students obtain and analyze their own DNA, which would be time-consuming, require molecular biology equipment, and could share sensitive personal DNA information in a group setting, I created an activity with playing cards. The cards represent different possible alleles of short tandem repeats (STRs), non-coding DNA often used in actual &ldquo;DNA fingerprinting.&rdquo; For the activity, students work in groups to simulate DNA fingerprinting using standard playing cards to represent alleles for two different STRs. Students then determine if this small amount of genotype information is enough to uniquely identify individuals in their group as well as between two student groups, and these data can also be used to analyze the entire class. Students draw images of DNA gels to create a visual representation of their STR data and see how differing STR sizes result in DNA band patterns. This lesson is adaptable for both introductory and upper division courses, requires very few materials, and can be completed in a single class session in either a laboratory room or a standard classroom. Students report enjoying the activity and that it helps them make the connection between alleles, genotypes, and DNA gels. <em>Primary Image:</em>&nbsp;Playing card genotypes and DNA gel drawing. An example of playing card &ldquo;genotypes&rdquo; for four individual students and the accompanying DNA fingerprint gel sketch. Drawing and photograph by AL Klocko.&nbsp;