DNA testing is a modern forensic procedure wherein a subject's DNA is collected (usually by taking a buccal smear, but also often from other tissues) and then compared to other specimens. It is useful in such cases as determining paternity and solving complex genealogical issues. It is perhaps best known in the field of criminal investigation, where it has recently been used to exonerate people who have been convicted of certain crimes; it is also frequently used as prosecutorial evidence, for example to show that a suspect was at the scene of a crime.
Testing is subject to the legal code of the jurisdiction in which it is performed. Usually the testing is voluntary, but it can be made compulsory by such instruments as a search warrant or court order.
In June of 2003, because of new DNA evidence, Dennis Halstead, John Kogut and John Restivo won a re-trial on their murder conviction. The three men had already served 18 years of their 30-plus year sentences.
See also: genetic fingerprinting, restriction fragment length polymorphism (RFLP), paternity test
