DNA(redirected from DNA ligase)
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n. scientifically, deoxyribonucleic acid, a chromonal 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 a hair, blood, 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.
DNAabbreviation for deoxyribonucleic acid, a chemical which is found in virtually every cell in the body and which carries genetic information. Except for identical twins, each person's DNA is unique. DNA profiling doesn't allow the examination of every single difference between people's DNA so the concentration will be on those aspects which are most likely to yield a difference. DNA can be extracted from any cells that contain a structure called the nucleus, for example, blood, semen, saliva or hair.
Mitochondrial DNA is inherited only from a person's mother. Brothers and sisters have the same mitochondrial DNA type as their mother. This feature of mitochondrial DNA can be used for body identification. The γ-chromosome is present only in men and is largely unchanged as it passes through the male line of a family. The usefulness of the technique in criminal matters is vastly enhanced by the extent to which it is possible to compare a sample with other individuals. To this end there is a National DNA Database maintained by the ASSOCIATION OF CHIEF POLICE OFFICERS and managed by the FORENSIC SCIENCE SERVICE. Techniques vary. There is a UK offence of DNA theft. It is also of assistance in paternity matters.