FORENSIC ANALYSIS

Forensic Analysis

Forensic Analysis

Introduction

Forensic Analysis is one of the oldest methods used for the detection of evidences in criminal scenes. It is noticed that, this method takes too much time but, it is highly accurate and, there are no possibilities that, result produced will be inadequate. The forensic analysis of blood and DNA provides the analysis for this case to investigate the original matter and, whole experiment has been conducted in the laboratory which takes several weeks for completion.

The diagnosis of forensic Analysis generic represents the first step of the investigation of the Laboratory medical, legal when, it comes to ascertain, whether a stain reddish both nature of blood, if a yellowish both constituted by saliva, semen or urine, if a fiber is natural or artificial. For these surveys, tests are carried out that are used to distinguish preliminary guidance, and evidence of certainty. The tests orientate are used as "screening" preliminary, being very sensitive and performed with very small amounts of material, but not as specific and it is necessary to perform other tests. The confirmation of the presence of blood, semen, saliva, etc, is obtained with techniques that give the certainty of the nature and the species of membership of the artifact, but have the disadvantage of requiring a fair amount of material, which sometimes can compromise subsequent investigations type identifier, which is extremely sensitive. In general, there are four methods for determining the presence of blood or DNA such as; the visual method, physical, microscopic, and chemical. Each of these, apart from the visual method, can give results of orientation and certainty. The visual method of immediate and direct realization is the preliminary stage that, even today, allows you to direct the search for traces and, subjected to the different laboratory test.

Methods

The Kastle, Meyer test, which is inexpensive, relatively easy to perform and gives quick results. In addition, it does not destroy DNA, thereby pursue other analyzes on the sample. Individualized studies, for the purpose of distribution of material evidence at the scene to individual persons. In modern forensics analyzes almost exclusively by highly variable, called short tandem repeats performed (STRs). Due to the high potential for discrimination of these markers, when examined several loci, an unambiguous assignment of a track to a person is possible. The investigation of mixing tracks and traces of biological material from more than one person is a particular challenge and, they usually leads to a mixed profile, i.e. the characteristics of all persons involved in a mixture are shown. Base composition and temperature show the behavior of DNA on agarose or not disturbed by it nor base composition temperature, unlike polyacrylamide gels. Composition of the electrophoresis buffer includes DNA mobility varies depending on the buffer used, if it has few low ion conductivity and DNA will migrate slowly and if the ion concentration is high temperature could reach the gel melt. Acrylamide gels are used to remove small DNA fragments (5,500pb), these gels permit separates fragments that differ only in ...