Scientifically, deoxyribonucleic acid, a chromosomal double chain (the famous “double helix”) in the nucleus of each living cell, the combination of which determines each individual’s hereditary characteristics. in law, the importance is the discovery that each person’s dna is different and is found in each living cell, so blood, hair, skin or any part of the body can be used to identify and distinguish an individual from all other people. dna testing can result in proof of one’s involvement or lack of involvement in a crime scene. while recent dna tests have proved a convicted killer on death row did not commit a crime and resulted in his release, current debate concerns whether dna evidence is scientifically certain enough to be admitted in trials. the trend is strongly in favor of admission.