Dna Research Paper

             DNA Research Paper

Characterization, or ''typing," of DNA for purposes of criminal investigation can be thought of as an extension of the forensic typing of blood that has been common for more than 50 years, it is actually an extension from the typing of proteins that are coded for by DNA to the typing of DNA itself. Genetically determined variation in proteins is the basis of blood groups, tissue types, and serum protein types. Developments in molecular genetics have made it possible to study the person-to-person differences in parts of DNA that are not involved in coding for proteins, and it is primarily these differences that are used in forensic applications of DNA typing to personal identification. The method was first used in casework in 1985 in the United Kingdom and first used in the United States by commercial laboratories in late 1986 and by the FBI in 1988. A case where they used DNA to find the murderer was in China in late July 2014. Homicide due to blunt force trauma, a dead male was found on a small farm road in a suburban area of a large Chinese city. At the crime scene, a red brick with blood stains was found near the victim. Investigators concluded the victim was killed by the red brick.Due to a significant amount of victim's blood on the brick, the double swab collection method could only collect the DNA information of the victim. The investigators tried to swab the areas of the brick void of the victim's blood with negative results. The surface of the brick was porous and difficult to collect the DNA evidence, contributing to the negative results.The areas of the brick that were visually free of victim blood were processed with the M-Vac wet-vacuum collection system. Approximately 200 mL of sterile surface rinse solution was sprayed down and collected from the brick surface. The liquid was then concentrated using a 0.45 micrometer Nalgene disposable filter apparatus. The filter was covered, labeled and set aside to dry using standard chain of custody practices. The evidence filter was removed from the filter apparatus and cut into small pieces with a sterile scalpel. The substrate was then processed using a membrane extraction kit to extract the DNA collected.  High quality DNA mixture was obtained. DNA analysis resulted in positive identification of the victim and another male suspect. The DNA profile was compared to the DNA database in China, resulting in a positive match and subsequent arrest of a male suspect. The suspect profile generated by the M-Vac System was a significant part of the evidence used to gain a confession. The case was concluded.