DNA

Video Link: https://www.findthemissing.org/how_it_works_video/NamusVideo640.htm

DNA has become an important piece in how society views forensic science. Again, due to popular culture, it is believed that every case must have DNA present; if a jury does not hear DNA evidence presented in court, the suspect may go free because the case was not solid without DNA evidence. DNA, in addition to gaining a conviction, can identify a missing person, deceased or alive. The Criminal Justice System utilizes DNA to its advantage.

DNA is the abbreviation for deoxyribonucleic acid, and is the fundamental building block for all living organisms (DNA Initiative). With the exception of identical twins, each person’s DNA is unique. DNA is a powerful tool for the Criminal Justice System. In combination with Locard’s Principle, a suspect will leave something at crime scene and take something away, DNA can link a suspect to the victim, victim to the suspect, and both to the crime scene. All that is needed is blood, bone, hair, or other body tissues and products.

Even with the smallest piece of DNA, the forensic laboratory can now create a profile of the perpetrator or missing person. The profile is formally called DNA fingerprinting or DNA typing (DNA Initiative). With the unknown sample from a scene and a known sample from the suspect, the laboratory can compare the two and either confirm suspicions or exclude an individual. Usually a range is given: the suspect’s DNA matches the unknown sample by 1:1.5 billion. This proves that the suspect is the only one who could have committed the crime, or the decomposed body is that of the missing girl.

In addition, to help solve cold cases or to exonerate those of innocence, a DNA database has been created. These databases are found at local, State, and national levels. Individuals convicted of felonious crimes must submit a DNA sample. The sample is entered in CODIS (Combined DNA Index System) where it will remain for any further crimes that an individual may commit (DNA Initiative).

http://www.dna.gov/