DNA Profiling in Forensic Science

The discovery of hypervariable minisatellite deoxyribonucleic acid (DNA) by Jeffreys and co-workers in 1985 provided forensic scientists with a means of discriminating between individuals that was many orders of magnitude greater than the traditional methods used before that date. Probably themost important forensic application of DNA profiling is in the identification of rapists. The original protein-based methods were difficult to interpret because both vaginal fluid and semenhave enzymeandbloodgroup activity, hence mixtures often occurred that were difficult to interpret. However, early experimentation with DNA demonstrated that it was relatively easy to separate sperm from other cellular material, effectively purifying the male from the female component and simplifying the interpretation. Since the original introduction of DNA profiling in the late 1980s, the technique has undoubtedly revolutionized the way in which forensic science laboratories work. The evolution of DNA profiling has also been dramatic over the past decade. In particular, the discovery of the polymerase chain reaction (PCR) opened up new possibilities including analysis of minute crime-stains that were not amenable to the original methods. In addition, the latest techniques are significantly faster and cheaper, and this led to the inception of theUKNationalDNAdatabase in 1995. It is envisaged that this will contain millions of DNA profiles within a few years. The speed of implementation of new technologies continues.Undoubtedly, within a few years, new techniqueswill enable even fastermethods of analysis, with corresponding benefits of reduced costs. Inevitably the use of DNA profiling in forensic science will become even more widespread than it is today. Historical, nonPolymerase Chain Reaction Methods