Restoration of the fragmented skull in expert human identification

Restoration of fragmented skull in expert personality identification is attained by assembly of bone fragments, modeling of bone defects by means of special plastic, and mathematical prediction of the lacking craniometric parameters. The authors suggest 111 equations of multiple linear regression which can be used in restoration of fragmented cerebral and facial parts of the skull. Prediction of craniometric parameters is useful for control and correction of plastic restoration of the skull. Regression equations are the most efficient in cases when the mandible is absent or in defects of symmetrical right- and left-side fragments of the skull. All stages of restoration are illustrated with examples from expert practice.     

Determining the human origin of fragments of burnt bone: a comparative study of histological, immunological and DNA techniques.

In situations where badly burnt fragments of bone are found, identification of their human or non-human origin may be impossible by gross morphology alone and other techniques have to be employed. In order to determine whether histological methods were redundant and should be superseded by biomolecular analyses, small fragments of artificially burnt bone (human and non-human) were examined by quantitative and standard light microscopy, and the findings compared with newer biomolecular analyses based on identifying specific human albumin by ELISA and amplifying human mitochondrial DNA by PCR. For quantitative microscopy, reference data were first created using burnt bones from 15 human and 20 common domestic and farm animals. Measured osteon and Haversian canal parameters were analysed using multivariate statistical methods. Highly significant differences were found between values for human and non-human bone, and a canonical discriminant function equation was derived, giving a predicted correct classification of 79%. For the main study, samples of cortical bone were taken from three fresh cadavers, six human skeletons and ten freshly slaughtered animals and burnt by exposure to temperatures ranging from 800 to 1200 degrees C; charred fragments of human cortical bone from two forensic cases were also tested. Quantitative microscopy and canonical discriminant function gave the correct origin of every sample. Standard microscopy falsely assigned burnt bone from one human skeleton and one forensic case to a non-human source, but otherwise gave correct results. Human albumin was identified in five individuals, including one of the forensic cases, but mitochondrial DNA could not be amplified from any of the human bone. No false positive test results were seen with either biomolecular method; and human albumin and mitochondrial DNA were correctly identified in all unburnt control specimens. It was concluded that histological methods were not redundant and that quantitative microscopy provided an accurate and consistent means of determining the human or non-human origin of burnt bone and was more reliable than standard microscopy or the newer immunological and DNA techniques tested here.     

Symmetrical fracturing of the skull from midline contact gunshot wounds: reconstruction of individual death histories from skeletonized human remains

This paper reports a bilaterally symmetrical cranio-facial fracture pattern that is observed in self-inflicted, midline gunshot wounds. Five cases of self-inflicted gunshots wounds are presented as follows: two high-powered rifle cases, two shotgun cases, and one handgun case. In all five cases the remains were either decomposing or skeletonized and submitted to forensic anthropologists. Following identification, the main focus of the anthropological examination was the analysis of perimortem trauma to the skeleton. In each case, the skull was submitted in a highly fragmented state. Nevertheless, by focusing on the pattern of perimortem cranio-facial fractures, the anthropologists contributed key information regarding the circumstances of death. The observed symmetrical cranio-facial fracture patterns in the above cases are described in detail and interpreted. The specific location of the linear fractures is discussed, as well as the theoretical rationale behind the location in terms of skeletal architecture, such as buttresses, struts, and sutures. The interpretive framework provided by this paper may prove helpful to others who are faced with similar cases of cranio-facial fracturing.     

Physical matches of bone, shell and tooth fragments: a validation study

The following study examines the reliability of physically matching fragments of bone and other mineral-based biological materials such as shells and teeth. Participants with varying education, training, and experience were asked to complete a matching exercise consisting of intentionally fragmented specimens. Success rates were very high; the positive association (correct match) rate was 0.925, while the nonassociation (overlooked match) rate was 0.075, and negative associations (incorrect matches) occurred at a rate of just 0.001. Results also indicate that those with more education and related experience tended to have higher positive association rates, although not significant statistically. Experienced osteologists, however, completed the matching exercise in significantly less time. Low error rates among both experienced and inexperienced individuals support the reliability and validity of performing physical matches of these materials, and suggest that performance may also be related to an individual's aptitude for spatial tasks or other factors.     

Development of a DNA-based macroarray for the detection and identification of Amanita species

A DNA-based macroarray was designed to quickly and accurately identify certain Amanita mushroom specimens at the species level. The macroarray included probes for Amanita phalloides and Amanita ocreata, toxic species responsible for most mushroom poisonings, and Amanita lanei and Amanita velosa, edible species sometimes confused with toxic species, based on sequences of the highly variable internal transcribed spacer (ITS) region of rDNA. A cryptic species related to A. ocreata and one related to A. lanei, identifiable by ITS sequences, were also included. Specific multiple oligonucleotide probes were spotted onto nylon membranes and the optimal hybridization temperatures were determined. The Amanita DNA array was highly specific, sensitive (0.5 ng DNA/μL and higher were detected), and reproducible. In two case studies, the method proved useful when only small amounts of mushroom tissue remained after a suspected poisoning. An identification could be completed in 12 h.     

Value of skull identification as evidence using a superimposed video image technic with reference to individual craniometric differences in the human skull

The possibility of using the video superimposition technique for the identification of a skull by comparing it with photographs of missing persons is based on the fact that the human skull, unlike any other part of the human skeleton, shows unmistakable individual characteristics. In order to obtain a quantification, the individuality of human skulls is defined in terms of craniometric data and their probability distribution. First calculations based on the coordinates of some important encephalometric points of 52 European skulls suggest that there are individual aspects comparable to those of fingerprints. Under certain conditions, the video superimposition technique can establish very strong evidence for the identity of an unknown skull, provided that it is applied correctly and carefully.     

Cross-national comparison of homicide: Age/sex-adjusted rates using the 1980 U.S. homicide experience as a standard

Cross-sectional studies of crime have typically relied on crude crime rates when making comparisons between countries. Crude rates control for population size but implicitly assume that all members of the population are equally at risk. Empirical studies have shown that, cross-nationally, risk varies by age and sex. Standardization of crime rates removes the confounding effects of variable age and sex population distributions. Since age/sex-specific crime rates are generally unavailable for many countries, the method of indirect standardization is the most desirable technique. Age/sex-adjusted homicide rates for 76 countries are presented, and two comparative measures are suggested. It is shown that while the United States has a higher homicide rate than all but 15 countries; in most cases, the magnitude of the difference, not controlling for age/sex differences, is overestimated. Crude rates underestimate differences between the United States and countries with higher rates of homicide.     

A review of the current understanding of burned bone as a source of DNA for human identification

Identification of incinerated human remains may rely on genetic analysis of burned bone which can prove far more challenging than fresh tissues. Severe thermal insult results in the destruction or denaturation of DNA in soft tissues, however genetic material may be preserved in the skeletal tissues. Considerations for DNA retrieval from these samples include low levels of exogenous DNA, the dense, mineralised nature of bone, and the presence of contamination, and qPCR inhibitors. This review collates current knowledge in three areas relating to optimising DNA recovery from burned bone: 1) impact of burning on bone and subsequent effects on sample collection, 2) difficulties of preparing burned samples for DNA extraction, and 3) protocols for bone decalcification and DNA extraction. Bone decalcification and various DNA extraction protocols have been tested and optimised for ancient bone, suggesting that prolonged EDTA (Ethylenediaminetetraacetic acid) demineralisation followed by solid-phased silica-based extraction techniques provide the greatest DNA yield. However, there is significantly less literature exploring the optimal protocol for incinerated bones. Although burned bone, like ancient and diagenetic bone, can be considered “low-copy”, the taphonomic processes occurring are likely different. As techniques developed for ancient samples are tailored to deal with bone that has been altered in a particular way, it is important to understand if burned bone undergoes similar or different changes. Currently the effects of burning on bone and the DNA within it is not fully understood. Future research should focus on increasing our understanding of the effects of heat on bone and on comparing the outcome of various DNA extraction protocols for these tissues.     

烧骨组织形态变化及DNA技术在个体识别中的应用

烧骨在火灾、焚尸、交通、爆炸等案件和事故的检材中具有特殊的地位。通过对不同条件焚烧下烧骨组织形态及DNA变化规律的研究,可为法医实践中烧骨的种属鉴定、性别及年龄判定提供准确的依据和标准,同时可利用残存的基因位点对烧骨残块进行个体识别和同一认定。烧骨DNA的提取方法及检测技术也在不断探索和改进。本文对烧骨在形态学、组织学和分子生物学水平研究进展以及烧骨评测的方法、技术进行概述,旨在为法医实践及进一步研究提供新的方法和思路。     

A DNA-based approach for the forensic identification of Asiatic black bear (Ursus thibetanus) in a traditional Asian medicine

Attempts to prevent illegal trade in bile and gallbladders from Asiatic black bears, Ursus thibetanus, are hampered by difficulties associated with identifying such items. We extracted DNA from bile crystals of unknown species origin and generated partial cytochrome b (cyt b) sequences using either universal primers (positioned in conserved regions of cyt b), or primers designed on existing U. thibetanus sequences (UT). Species origin was determined by aligning resolved sequences to reference sequence data. The universal primers were unsuitable for U. thibetanus identification when multiple species templates were present in the samples. The UT primers amplified U. thibetanus DNA from all sample extracts, including those containing mixed species templates. The amplified fragment can distinguish U. thibetanus from the most closely related species, U. americanus, a distinct advantage of DNA sequencing over the methods currently used to analyze suspected U. thibetanus bile.     

DNA-based identification of big cats and traditional Chinese medicine artifacts in the Czech Republic

The aim of this study is to provide an overview of ongoing research on and the development of identification tools for big cats (Panthera tigris, Panthera leo, Panthera pardus, …). The set of tools includes a species-specific RTPCR quantitation system (nuclear and mitochondrial), STR multiplexes, a rapid system for big cat species determination, and a database solution.     

Role of orthopedic implants and bone morphology in the identification of human remains

When conventional methods of identification, such as visual recognition and dental comparison, cannot be used to identify a deceased person, it becomes necessary to consider alternative methods. The presence of an orthopedic implant in a body may assist identification if ante-mortem medical records are available for comparison. Another method of identification involves comparison of ante-mortem and postmortem radiographs. Eight cases are reported from Forensic Science SA where the presence of orthopedic implants and/or ante-mortem radiographs were used to try to establish identification. In six cases, positive identification was established, and in two cases with upper limb orthopedic implants, the bones remained unidentified. Manufacturers were unable to provide any information about the distribution and use of the implants that could be of use with identification, as there are no requirements in Australia for individual medical implants to be tracked. Such a system has the potential to aid postmortem identification if serial codes were etched onto implants that could then be traced to manufacturers, surgeons, and recipients of these devices.     

A decade of pediatric homicide: a retrospective study at the Medical University of South Carolina.

More than 3 million children are abused and/or neglected each year in the United States. Unfortunately, a significant percentage of these cases result in homicide by child abuse or child neglect. Causes of death range from blunt force trauma and shaking to asphyxia to immolation. We retrospectively reviewed all pediatric forensic cases referred to the Medical University of South Carolina Forensic Pathology Section over the past 10 years, from January 1986 to December 1995. Of these, we looked only at children < or =5 years of age. The majority (342 cases, 69%) of these deaths were classified as natural, 96 (19%) as accident, and 60 (12%) as homicide. Of the homicides, we examined the cause of death; age, gender, and race of the victim; relationship to the perpetrator; time interval between injury and death; and the initial history given as to the cause of the injury. The cause of death fell into nine categories, the number one category being head trauma. Forty-five percent of the homicides were by head trauma, 12% by abdominal or body trauma, 25% by asphyxia (with half of these due to drowning), 10% by carbon monoxide poisoning or thermal injury, and the remaining 8% involving cases of neglect, stabbing, and poisoning. The majority of the homicide victims were male (67%) and black (67%). Forty-six percent were < or =1 year of age. Approximately 25% of the homicide cases were designated as shaken baby syndrome (SBS). In 97% of the cases, the assailant was known to the victim and was a family relative in 77%. Sixty-three percent of the assailants were female and 45% of the assailants were male; in 12%, the assailants were both parents, and in 1 case, the assailant remains unknown. Of the asphyxia deaths, 87% of the assailants were female. The time interval between injury and death ranged from minutes to hours in most cases to months in cases of repeated abuse and chronic injury and sequelae. The time interval between injury and the onset of symptoms remains unknown in most cases due to inconsistencies in the history and lack of credibility of the caretaker. The most common initial history given was "a fall" (20%). We report our findings of a decade of pediatric homicides to increase awareness of the common scenarios and case histories, demographics of the victims, causes of death, and perpetrators of pediatric homicide.     

The computer and the law: coordinate analysis of skull shape and possible methods of postmortem identification.

Mechanisms accelerating or retarding the disintegration of soft tissues are briefly discussed, as well as the need to reconstruct the missing profile for postmortem identification purposes. The application of X-ray and computer-based analyses is discussed in the context of providing data to predict and reconstruct the most probable soft tissue profile of a dry skull. In addition, information from extensive studies of the facial bones and profiles of veterans has been applied to methods in forensic medicine of determining age, sex, and racial background of unknown subjects.     

Positive identification by a skull with multiple epigenetic traits and abnormal structure of the neurocranium, viscerocranium, and the skeleton

Wormian bones are small ossicles appearing within the cranial sutures in more than 40% of skulls, most commonly at the lambdoid suture and pterion. During the skeletal analysis of an unidentified male war victim, we observed multiple wormian bones and a patent metopic suture. Additionally, the right elbow was deformed, probably as a consequence of an old trauma. The skull was analyzed by cranial measurements and computerized tomography, revealing the presence of cranial deformities including hyperbrachicrania, localized reduction in hemispheral widths, increased cranial capacity, and sclerosis of the viscerocranium. Besides unique anatomical features and their anthropological value, such skeletal abnormalities also have a forensic value as the evidence to support the final identification of the victim.     

A time course study on STR profiles derived from human bone, muscle, and bone marrow.

The use of the polymerase chain reaction (PCR) to define deoxyribonucleic acid (DNA) types at several loci was investigated. PCR was used to amplify nine short tandem repeat (STR) loci along with the amelogenin locus on the X and Y chromosomes using the AmpF/STR Profiler Plus PCR amplification kit (Perkin Elmer). Rib bones were collected from 12 individuals. Five cm portions were buried at a depth of approximately 30 cm and 5 cm portions were left on the surface of the ground. Samples were exposed to the environment for periods of time ranging from two weeks to 17 months. Dried blood standards were prepared for use as reference standards for each rib sample. Bone, muscle, and bone marrow were collected from each sample. DNA from each tissue type was extracted. Complete profile results were obtained from the surface bone samples out to an exposure time of 17 months. None of the muscle or bone marrow samples produced complete profile results beyond eight weeks. All DNA typing results from complete or incomplete profiles were consistent with DNA typing results of the corresponding blood standard. Results suggest that using the AmpF/STR Profiler Plus PCR Amplification Kit is a valid way to establish the DNA profile of tissue types from human remains.     

Bayesian networks for DNA-based kinship analysis: Functionality and validation of the GENis missing person identification module

GENis is a recently published open-source multi-tier information system developed to run forensic DNA databases. It relies on a Bayesian Networks framework and it is particularly well suited to efficiently perform large-size queries against databases of missing individuals. In this contribution we present a validation of the missing person identification capabilities of GENis. To that end we introduce fbnet, a free-software package written in the R statistical language that implements the complete GENis functionality to perform kinship analysis based on DNA profiles. With the aid of fbnet, we could validate likelihood ratios against estimations draw with Familias and forrel (two well-recognized R packages for kinship quantification) for complex pedigrees provided by the Argentinian reference databank (Banco Nacional de Datos Geneticos, BNDG). We found that our methodological approach presented an excellent performance in terms of accuracy and computation times.