Forensic DNA Typing Protocols PDF

The discovery of polymorphisms in repetitive DNA by Dr. Alec Jeffreys and coworkers in 1985 has had a tremendous impact on forensic genetics. Since then we have witnessed a revolution in the field of forensic identification, and different markers and technologies for DNA typing have moved at a breathtaking pace. Rapid advances in technology, from serological or electrophoretic analysis of protein polymorphisms to direct investigation of the underlying DNA polymorphisms, occurred in a very short space of time in the mid-1980s. Consequently, the incorporation of modern molecular biological techniques in the forensic genetic laboratory has resulted in major benefits for justice. DNA analysis has become the standard method applied by most forensic genetic labs, especially in criminal forensic casework (e.g., analysis of stains and hairs, identification of human remains, and paternity testing).

Polymerase chain reaction (PCR)-based DNA typing systems have made it possible to analyze DNA obtained from only a few cells as well as from highly degraded human samples (recently demonstrated by the identification of relatively old human remains). The potential of DNA typing has made possible the resolution of immigration problems and complicated paternity testing cases when the father is not available. Rapid identification of individuals in mass disaster using DNA typing has also been possible. Computerized DNA databases for the identification of criminal offenders have been created in some countries. Owing to these many impressive applications, the media have taken great interest in DNA profiling, mainly because of the value of the evidence presented through DNA profiling in certain well-known legal cases. Initially, the use of DNA profiling was very controversial in some countries, perhaps because of a hasty introduction of this new methodology. Ironically, however, this has contributed to a much more reliable use of DNA profiling. Two parallel upheavals concerning the introduction of DNA typing technology have been accountable for the aforementioned: the introduction of quality control and accreditation schemes and, in particular, the spreading use of the statistics in the evaluation of DNA evidence. Also, progress in standardizing the tests has proven even more important than the technical advances.