Histopathological study and DNA analysis feasibility from compact bone of femoral skeletal human remains. applications in forensic identification

Abstract

Recently, investigations of genetic linkage and human identification through DNA analysis have been required for several types of cases. A challenge commonly encountered occurs when the DNA sample is highly degraded. There are many cases in which post-mortem human bones that have been exposed to adverse environmental conditions and contaminants are the only materials available for analysis. Brazil apart from its continental territory, presents different environmental conditions in comparison of other countries. The tropical climate can damage the bone material that has been exposed to these conditions and cause changes in the microstructure and cell loss, factors that complicate the analysis of DNA. In such cases, the analysis of DNA regions of short tandem repeats (short tandem repeats - STRs) , used routinely in most DNA laboratories for human identification often fail by not providing complete genetic profiles. Thus, the use of autosomal markers that can amplify shorter fragments than the STR used in the routine procedures and the use of different methods of DNA extraction are possible solutions.This work has two objectives:a) to study the microstructure of the femoral compact bone tissue of biological samples, which were subjected to harsh environmental conditions in southeastern Brazil; b)recover DNA and obtain the genetic profile of these samples. For this study, bone fragments will be used to compact the femoral diaphysis of 20 skeletonized corpses found in the region of Ribeirao Preto, São Paulo, Brazil. Will be held the making of histological slides of the samples, which wil be stained with hematoxylin and eosin followed by morphological analysis. DNA will be extracted using organic extraction methods and amplified using silica based commercial kits for analyses of conventional amplification short tandem repeats (STR) kits and the mini-STR kit. (AU)