DNA fingerprinting can be used for positive identification in criminal investigations. DNA can be found in which sources?

• A. Blood
• B. Semen
• C. Body Fluids
• D. All of the above

Answer: (D)

DNA fingerprinting works by analyzing genetic material that comes from a biological sample. DNA is present in many bodily materials because it resides in the nuclei of cells. In blood, DNA comes from white blood cells (red blood cells don’t have nuclei, but blood samples still yield DNA due to the white cells). Semen contains DNA in the sperm. And many other body fluids—such as saliva, urine, sweat, vaginal secretions, etc.—can carry cells or other DNA material that can be analyzed. Because you can obtain DNA from all of these sources, any of them can be used for identification. That’s why the best choice is all of the above.