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Convicted by a Hair

NCJ Number
119172
Journal
Criminal Justice Volume: 4 Issue: 2 Dated: (Summer 1989) Pages: 5-7,41-43
Author(s)
J A Tarantino
Date Published
1989
Length
5 pages
Annotation
Identification through DNA testing is being heralded as a revolutionary advance in scientific evidence.
Abstract
Because of the makeup of the human genetic code, no two humans, except for identical twins, have exactly the same total DNA sequence. The goal of DNA typing is to detect differences between DNA samples taken from different individuals. DNA print identification involves five steps: DNA extraction, fragmentation, gel electrophoresis, hybridization, and autoradiograph. These steps are explained in detail, along with the Cetus test sequences. The companies marketing DNA-typing tests assert that the odds of misidentification are one in 30 billion which leads courts and juries to assume the problem of reasonable doubt has been effectively dealt with. However, it is noted that this evidence is "probabilistic, not conclusive." Misidentification can occur when two different DNA types are mistaken for one another or there is a possibility of lab and protocol error. DNA identification in court is discussed, although there has been little in the way of reported decisions. Regarding the future of DNA identification, fundamental fairness and self-incrimination are discussed.