In forensic DNA analysis, the DNA from the crime scene is compared to which to determine a match?

• A. The suspect's DNA
• B. The victim's DNA
• C. The lab technician's DNA
• D. The witnesses' DNA

Answer: (A)

DNA profiling compares the genetic pattern found in the crime-scene material to reference DNA from people who could have contributed to that material. The most informative and direct comparison is with the suspect’s DNA, if a reference sample is available, because a match supports that the suspect left DNA at the scene. The victim’s DNA might be present, but it would indicate the victim contributed DNA, not identify the perpetrator. Contamination from a lab technician is an issue to avoid, and witnesses’ DNA would only be considered if they could plausibly have contributed. The key idea is: a crime-scene DNA profile is tested against a known reference profile, with the suspect’s DNA being the primary reference when testing for a link to the crime.