DNA

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DNA

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.

DNA

abbreviation 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.

References in periodicals archive ?
When we now add DNA ligase, these adapters can anneal to and then ligate to put known, defined sequence "caps" on all of the fragment types present.
Vindigni, "Interaction of the Ku heterodimer with the DNA ligase IV/Xrcc4 complex and its regulation by DNA-PK," DNA Repair, vol.
(1997) Activity of DNA ligase IV stimulated by complex formation with XRCC4 protein in mammalian cells.
Improving the fidelity of thermos thermophilus DNA ligase. Nucleic Acids Res.
The insert and vector were then ligated using T4 DNA ligase following the manufacturer's protocol.
Ligation was carried out using T4 DNA Ligase (Promega) in a 4[degrees]C overnight reaction.
The ligation mixture consists of 1 [micro]l of pUC19 vector, 9 [micro]l of 2x ligation buffer, 1 [micro]l of T4 DNA ligase, 4.28 ul of deionized distilled water and 0.72 [micro]l of insert, to a total volume of 10 [micro]l.
The restriction-ligation reactions consisted of 0.5 [micro]l 10x T4 buffer, 0.2[micro]l T4 DNA ligase (3[micro]/ [micro]l), 0.5[micro]l Tru9'adaptor forward, 0.5[micro]l Tru9' adaptor backward, 0.5[micro]l EcoRI adaptor forward, 0.5[micro]l EcoRI adaptor backward and 2.3[micro]l ddH2O.
After three hours at 37 [degrees]C, 10 [micro]L of a ligation mix containing 5.5 ng of EcoR1 adapter, 1 mM ATP, 33 mM Tris-acetate (pH 7.9), 10 mM magnesium acetate, 66 mM potassium acetate, 0.1 mg/mL BSA and 2 U T4 DNA ligase (MBI Fermentas) were added.
Each ligation reaction (20 [micro]L) contained the restriction digestion product (10 [micro]L), 1 x T4 DNA ligase buffer with EDTA, 0.05 M NACl, 0.05 mg [mL.sup.-1] BSA, 6 U T4 DNA ligase, 10-pmol EcoRI adapter, 100-pmol MseI adapter and appropriate amount of water.
Restriction enzymes and T4 DNA ligase were purchased from New England Biolabs (NEB).