Analysis of DNA polymorphisms from pubic hair and head hair for human identification

Abstract

Because of the increase in violence, in general, the use of this method of analysis in forensic routine has become imperative in forensic routine. For the other hand, the biological vestiges as pubic hair and head hair, is one of most frequently found in crime scene or in decompoded bodies. The analysis of DNA could be considered one of the main technical advances in forensic human identification methods since the doscovery of the fingerprints. The analysis of DNA for the human identification uses the genetic profile of an individual based on the combination of diversity of markers that are inherited from their progenitors. These markers are generally differences in the nuclear DNA sequences from individuals (polymorphisms). In some cases, however, the analysis of DNA from the nucleus can not be applied. Usually, this happens when the DNA of the sample is degraded or in cases where the biological material does not contain nuclear DNA that is analyzable. In such cases, the analysis of mitochondrial DNA (DNA mt) is the method of choice. However, in the same individual there could be different populations of mit DNA, a phenomenon called heteroplasmia. The objective of this study is to analyze and to characterize the morphological features of pubic hair and head hair at different phases of growth (anagen, telogen and catagen), as well as to analyze the polimorphisms of the DNA (nuclear and mitocondrial) in such samples, in order to further understand and use them in forensic investigation. Fragments of short tandem repeats and the HV1 and HV2 sequencing after PCR, from samples of blood, pubic hair and head hair will be analyzed. All the samples are collected from 200 individual from the Public Service of Necropsy at Hospital das Clínicas da Faculdade de Medicina da USP. The analysis will be carried out in the laboratories of the Federal University of São Paulo - Medicine School (UNIFESP). Taking into account the level of technological advance, the high analytical power, and the increasing influence of DNA profiles in the forensic field, this project has the objective of entirely developing scientific procedures, establishing interchange and technical-scientific collaboration between Academic Institutions (UNIFESP and USP), as well as promoting the education, training and specialization of professionals (postgraduate students) for research with biological vestiges in forensic applications. This research has been developed since 2004 (approved by the Ethical Committee for Research Projects Analysis - CAPPesq protocol number 777/04), with initial results already presented in Scientific Congress. (AU)