DNA contains genetic information found in chromosomes in our cells. It is made up of a backbone, sugars, phosphates, and nitrogen base pairs (adenine pairs with thymine, and guanine pairs with cytosine). DNA is unique between individuals and can be used in forensic science to identify suspects and victims. DNA evidence can link suspects to crime scenes, eliminate suspects, identify victims through relatives, and connect multiple crime scenes to the same perpetrator. Factors like environment, heat, and bacteria can degrade DNA evidence over time. CODIS is a DNA database that can help identify suspects when no prior suspect existed.