Students will use PCR to amplify their own DNA and compare it to a sample obtained from a hypothetical crime scene to try to rule themselves out as a suspect. Variable number tandem repeats (VNTRs) are regions in a genome that contain short stretches of DNA repeated a number of times. The number of repeats in a particular VNTR can vary from individual to individual. In this way, genetic variation in VNTRs can be used as markers for personal identification. This hands-on activity lets students explore molecular biology in personal identification and forensics, as well as inheritance, human genetics, DNA polymorphisms, and genetic diversity.