Forensic applications of DNA fingerprinting

In many ways, DNA profiling technology is very similar to the conventional techniques used for forensic identification. As with, for example, blood grouping techniques, the molecular characteristics of the scene of crime sample may be determined and compared with those of the scene of reference samples from suspects and victim. If the molecular characteristics of the crime sample and the suspect are different, then they cannot be from the same person, whereas if they match, then the possibility remains that they may be from a single source. Similar material, such as blood or semen stains, may be used for both biochemical and genetic tests, and the main applications of identification and relationship testing are shared by both techniques. At this point, the similarity ends; DNA profiling has the following characteristics: 1. It is more sensitive, being able to generate sound data from only a tiny amount of even partially degraded biological material. 2. It is capable of resolving mixtures of semen or tissue from up to several individuals. 3. It has a far greater power of discrimination between individuals--sometimes up to 1 millionfold higher than conventional techniques. 4. It provides considerably more information on the nature of relationships, particularly in cases of incest. As such, the technique represents a quantum leap in forensic identification and relationship testing.