Identification of fragmented bones based on anthropological and DNA analyses: case report

Evaluation of different methods for DNA extraction from human burnt bones and the generation of genetic profiles for identification

Bone exposure to heat in the presence of moisture breaks the phosphodiester bonds of the backbone, leaving sheared DNA in bone cells. This also limits the possibility of generating a complete profile of the victim. With the increasing incidence of fire outbreaks over the past few years, a paradigm shift to establish identity has been observed, from morphological identification of victims to STR profiling. For this study, 10 bone samples were taken from burnt human bodies that were recovered from different fire outbreak scenes. The DNA from these burnt human tissues was isolated using four different extraction methods: the organic extraction method, the total demineralisation method, the Qiagen kit method, and the Chelex extraction method. STR profiles of victims were generated on a genetic analyser using an AmpFlSTR Identifiler® Plus Kit and analysed on Gene Mapper ID-X. DNA isolated from bones using the total demineralisation extraction method and organic extraction method was of the highest quality due to the efficient removal of inhibitors. DNA obtained using these two methods successfully generated the STR profiles of the victims. The quality of isolated DNA obtained through the Qiagen kit was comparatively low, but STR profiles of the victims were successfully generated. The Chelex kit failed to extract good quality DNA of high quantity from the burnt bones, encountering inhibition in all samples at varying degrees. This study concludes that total demineralisation and the Qiagen kit are sophisticated and reliable methods to obtain a good yield of DNA from burnt human bones, which can be used for the identification of victims.

Kinship analysis using DNA typing from five skeletal remains with an unusual postmortem course

The skeletal remains of five individuals with an unusual postmortem course were discovered in a house. According to the explanation of the putative bereaved family, the postmortem interval of the five remains was between five and 20 years. They also explained to the police that they and the dead family members believed that the dead can be resurrected, and they had kept the bodies indoors, so the bodies had followed an unusual postmortem course. The five dead were identified by kinship analysis using DNA typing. For DNA extraction, we used the DNA extraction method with ultrafiltration and a silica-based DNA extraction kit. As a result, complete amplification STR profiles were obtained from DNA from bone samples of all five skeletons and their identity was proven by kinship testing.

Development of species identification tests targeting the 16S ribosomal RNA coding region in mitochondrial DNA

This report describes the development of a species testing system based on the diversity of nucleotide sequences in mitochondrial DNA (mtDNA) among species. Five species, human, cow, pig, dog, and cat, were considered. The partial nucleotide sequences in 16S ribosomal RNA coding region were chosen as the target for discriminating the species. The sequence diversities of this approximately 400 bp long region ranged from 15.7 to 24.1% among the five species. Sequencing analysis of this target on 50 individuals of each species (53 for dogs) revealed that the nucleotide sequences were well preserved within species. Species-specific PCR for each species was also designed, and satisfactory results with regard to both sensitivity and specificity were obtained. A validation study with DNA extracted from bovine bone exposed to the environment revealed that the PCRs designed in this study worked correctly. From the results obtained, it was shown that this testing system could be a good tool for species identification. One successful case report is also demonstrated.

DNA typing of bone specimens—the potential use of the profiler test as a tool for bone identification

Twenty-six bone DNA identification cases are described. The postmortem periods of the studied remains ranged from three days to over 30 years, and the locations where the remains were found varied resulting in a variety of postmortem conditions. Nuclear DNA typing using an AmpFLSTR Profiler kit and mitochondrial DNA (mtDNA) typing of hypervariable regions 1 and 2 (HV1 and HV2) in a control region were performed both with decalcified and non-treated bone powder samples. Decalcification was shown to improve the success of DNA typing. The nucleotide sequences of the HV1 and HV2 regions were successfully determined in all cases examined. Nuclear DNA typing was very successful, more than half of the loci were typed during multiple amplifications (10 loci in one reaction) in 23 cases. Polymerase chain reaction (PCR) inhibition was observed in five cases including three samples that were found buried in soil. This inhibitory effect was identified as the result of unbalanced multiple PCR during the profiler test. These results revealed that DNA typing targeting nuclear DNA is a potentially powerful tool for bone identification.

Influence of post-mortem changes on DNA typing (D1S80, TH01, HLA DQA 1, and PM typing system): case studies for personal identification

Between 1996 and 2002, we tested a total of 20 unidentified bodies for DNA typing. We describe here the relationships among detection rates achieved by four DNA typing systems (D1S80 typing, TH01 typing, HLA DQA1 typing, and PM typings), the post-mortem interval, types of specimens (bone, nail, and blood), post-mortem changes, and the site at which the corpse was found (indoors, outdoor, or in the sea). Detection rates for PM typings, HLA DQA1 typing, TH01 typing, and D1S80 typing in all cases were 94.7, 90.0, 73.7, and 50.0%, respectively. The success of the typings was highly influenced by the post-mortem interval. Using blood, almost all DNA types were detected, while the nail showed comparatively higher detection rates than bone. The detection rate decreased in order with indoor, outdoor, sea, and soil as the site at which the corpse was found. It is important to consider the specimen, the site at which the corpse was found, and the post-mortem interval to successfully achieve DNA typing.