Showing papers in "International Journal of Legal Medicine in 2011"

Multi-phase post-mortem CT angiography: development of a standardized protocol

Abstract: The objective of this work was to develop an easily applicable technique and a standardized protocol for high-quality post-mortem angiography. This protocol should (1) increase the radiological interpretation by decreasing artifacts due to the perfusion and by reaching a complete filling of the vascular system and (2) ease and standardize the execution of the examination. To this aim, 45 human corpses were investigated by post-mortem computed tomography (CT) angiography using different perfusion protocols, a modified heart-lung machine and a new contrast agent mixture, specifically developed for post-mortem investigations. The quality of the CT angiographies was evaluated radiologically by observing the filling of the vascular system and assessing the interpretability of the resulting images and by comparing radiological diagnoses to conventional autopsy conclusions. Post-mortem angiography yielded satisfactory results provided that the volumes of the injected contrast agent mixture were high enough to completely fill the vascular system. In order to avoid artifacts due to the post-mortem perfusion, a minimum of three angiographic phases and one native scan had to be performed. These findings were taken into account to develop a protocol for quality post-mortem CT angiography that minimizes the risk of radiological misinterpretation. The proposed protocol is easy applicable in a standardized way and yields high-quality radiologically interpretable visualization of the vascular system in post-mortem investigations.

Accuracy of Cameriere, Haavikko, and Willems radiographic methods on age estimation on Bosnian–Herzegovian children age groups 6–13

Abstract: The aim of this cross-sectional study was to compare the accuracy of the Cameriere European formula (Cameriere), adopted Haavikko method from 1974 (Haavikko), and revisited Demirjian method by Willems (Willems) for age estimation on orthopantomograms (OPGs) of Bosnian–Herzegovian (BH) children age groups 6–13 years. The accuracy was determined as difference between estimated dental age (DA) and chronological age (CA) and the absolute accuracy (absolute difference) was assessed by analyzing OPGs of 591 girls and 498 boys. The Cameriere method overestimated the mean age by 0.09 year for girls and underestimated by −0.02 year for boys. The Haavikko method underestimated the mean age by −0.29 year for girls and −0.09 year for boys. The Willems method overestimated the mean age by 0.24 year in girls and by 0.42 year in boys. The absolute accuracies were 0.53 year for girls and 0.55 year for boys for Cameriere method; for Haavikko method, 0.59 year for girls and 0.62 year for boys; and for Willems method 0.69 year for girls and 0.67 year for boys. In conclusion, Cameriere method is the most accurate for estimating the age of BH children age groups 6–13 years using OPGs, following adopted Haavikko method and Willems method.

Targeted post-mortem computed tomography cardiac angiography: proof of concept

Abstract: With the increasing use and availability of multi-detector computed tomography and magnetic resonance imaging in autopsy practice, there has been an international push towards the development of the so-called near virtual autopsy. However, currently, a significant obstacle to the consideration as to whether or not near virtual autopsies could one day replace the conventional invasive autopsy is the failure of post-mortem imaging to yield detailed information concerning the coronary arteries. To date, a cost-effective, practical solution to allow high throughput imaging has not been presented within the forensic literature. We present a proof of concept paper describing a simple, quick, cost-effective, manual, targeted in situ post-mortem cardiac angiography method using a minimally invasive approach, to be used with multi-detector computed tomography for high throughput cadaveric imaging which can be used in permanent or temporary mortuaries.

DNA-based identification of forensically important Australian Sarcophagidae (Diptera).

Abstract: The utility of the forensically important Sarcophagidae (Diptera) for time since death estimates has been severely limited, as morphological identification is difficult and thermobiological histories are inadequately documented. A molecular identification method involving the sequencing of a 658-bp ‘barcode’ fragment of the mitochondrial cytochrome oxidase subunit I (COI) gene from 85 specimens, representing 16 Australian species from varying populations, was evaluated. Nucleotide sequence divergences were calculated using the Kimura-two-parameter distance model and a neighbour-joining phylogenetic tree generated. All species were resolved as reciprocally monophyletic, except Sarcophaga dux. Intraspecific and interspecific variation ranged from 0.000% to 1.499% (SE = 0.044%) and 6.658% to 8.983% (SE = 0.653%), respectively. The COI ‘barcode’ sequence was found to be suitable for the molecular identification of the studied Australian Sarcophagidae: 96.5% of the examined specimens were assigned to the correct species. Given that the sarcophagid fauna is poorly described, it is feasible that the few incorrectly assigned specimens represent cryptic species. The results of this research will be instrumental for implementation of the Australian Sarcophagidae in forensic entomology.

RNA integrity in post-mortem samples: influencing parameters and implications on RT-qPCR assays

Abstract: Messenger RNA (mRNA) profiling in post-mortem human tissue might reveal information about gene expression at the time point of death or close to it. When working with post-mortem human tissue, one is confronted with a natural RNA degradation caused by several parameters which are not yet fully understood. The aims of the present study were to analyse the influence of impaired RNA integrity on the reliability of quantitative gene expression data and to identify ante- and post-mortem parameters that might lead to reduced RNA integrities in post-mortem human brain, cardiac muscle and skeletal muscle tissues. Furthermore, this study determined the impact of several parameters like type of tissue, age at death, gender and body mass index (BMI), as well as duration of agony, cause of death and post-mortem interval on the RNA integrity. The influence of RNA integrity on the reliability of quantitative gene expression data was analysed by generating degradation profiles for three gene transcripts. Based on the deduced cycle of quantification data, this study shows that reverse transcription quantitative polymerase chain reaction (RT-qPCR) performance is affected by impaired RNA integrity. Depending on the transcript and tissue type, a shift in cycle threshold values of up to two cycles was observed. Determining RNA integrity number of 136 post-mortem samples revealed significantly different RNA qualities among the three tissue types with brain revealing significantly lower integrities compared to skeletal and cardiac muscle. The body mass index was found to influence RNA integrity in skeletal muscle tissue (M. iliopsoas). Samples originating from deceased with a BMI > 25 were of significantly lower integrity compared to samples from normal weight donors. Correct data normalisation was found to partly diminish the effects caused by impaired RNA quality. Nevertheless, it can be concluded that in post-mortem tissue with low RNA integrity numbers, the detection of large differences in gene expression activities might still be possible, whereas small expression differences are prone to misinterpretation due to degradation. Thus, when working with post-mortem samples, we recommend generating degradation profiles for all transcripts of interest in order to reveal detection limits of RT-qPCR assays.

mRNA-based skin identification for forensic applications

Abstract: Although the identification of human skin cells is of important relevance in many forensic cases, there is currently no reliable method available. Here, we present a highly specific and sensitive messenger RNA (mRNA) approach for skin identification, meeting the key requirements in forensic analyses. We examined 11 candidate genes with skin-specific expression, as ascertained from expression databases and the literature, as well as five candidate reference genes ascertained from previous studies, in skin samples and in other forensically relevant tissues. We identified mRNA transcripts from three genes CDSN, LOR and KRT9, showing strong over-expression in skin samples relative to samples from forensic body fluids, making them suitable markers for skin identification. Out of the candidate reference genes tested, only ACTB showed similarly high expression in skin and body-fluid samples, providing a suitable reference marker for quantitative real-time PCR (qPCR) analysis of skin. Analyses of palmar and thumbprint skin samples indicate that our qPCR approach for the three skin-targeted mRNA markers, as well as the reference mRNA marker ACTB, is highly sensitive, allowing successful detection of minute amounts of skin material including full, half and quarter thumbprints, albeit with decreased success in decreasing print material. Furthermore, thumbprints stored for 6.5 months provided similar results relative to freshly analysed samples implying reasonable time-wise stability of the three skin-targeted mRNAs as well as the ACTB reference mRNA. Our study represents the first attempt towards reliable mRNA-based skin identification in forensic applications with particular relevance for future trace/touched object analyses in forensic case work. Although the approach for skin identification introduced here can be informative when applied on its own, we recommend for increased reliability the integration of (one or more of) the skin-targeted mRNA markers presented here into multiplex assays additionally including mRNA markers targeting alternative cell types expected in forensic samples.

Applicability of Greulich and Pyle method for age assessment in forensic practice on an Italian sample

Abstract: The main importance in age estimation lies in the assessment of criminal liability and protection of unaccompanied minor immigrants, when their age is unknown. Under Italian law, persons are not criminally responsible before they reach the age of 14. The age of 18 is important when deciding whether juvenile or adult law must be applied. In the case of unaccompanied minors, it is important to assess age in order to establish special protective measures, and correct age estimation may prevent a person over 18 from benefiting from measures reserved for minors. Since the Greulich and Pyle method is one of the most frequently used in age estimation, the aim of this study was to assess the reproducibility and accuracy of the method on a large Italian sample of teenagers, to ascertain the applicability of the Atlas at the critical age thresholds of 14 and 18 years. This retrospective study examined posteroanterior X-ray projections of hand and wrist from 484 Italian–Caucasian young people (125 females, 359 males) between 11 and 19 years old. All radiographic images were taken from trauma patients hospitalized in the Azienda Ospedaliero Universitaria Ospedali Riuniti of Ancona (Italy) between 2006 and 2007. Two physicians analyzed all radiographic images separately. The blind method was used. In the case of an estimated age of 14 years old, the true age ranged from 12.2 to 15.9 years (median, 14.3 years, interquartile range, 1.0 years) for males, and 12.6 to 15.7 years (median, 14.2 years, interquartile range, 1.7 years) for females. In the case of an estimated age of 18 years, the true age ranged from 15.6 to 19.7 years (median, 17.7 years, interquartile range, 1.4 years) for males, and from 16.2 to 20.0 years (median, 18.7 years, interquartile range, 1.8 years) for females. Our study shows that although the GPM is a reproducible and repeatable method, there is a wide margin of error in the estimation of chronological age, mainly in the critical estimated ages of 14 and 18 years old in both males and females.

Population genetic analyses of the NGM STR loci

Abstract: The AmpFlSTR® NGM™ PCR Amplification Kit enables amplification of 15 autosomal short tandem repeat (STR) loci. The loci are the ten STRs in the SGM Plus® Kit plus the EDNAP and ENSFI recommended STRs D10S1248, D22S1045, D2S441, D1S1656, and D12S391. Allele frequency and other forensically relevant statistics data were generated for the NGM loci in three US population groups (African Americans, Caucasians, and Hispanics). The analyses support that the NGM multiplex is one of the most informative STR multiplex kits available to the forensic science community. At the population level, there are no more detectable departures from expectations of the independence of alleles within as well as between loci than would be expected due to chance, even for the two syntenic loci vWA and D12S391; however, linkage analysis in three large pedigree families shows close linkage between these two loci with a recombination fraction of 0.108. Therefore, in contrast to the practices in calculating the rarity of a DNA profile, for kinship analyses independence between the loci, vWA and D12S391 cannot be assumed.

Sonographic evaluation of apophyseal ossification of the iliac crest in forensic age diagnostics in living individuals

Abstract: Due to the requirement to minimise exposure to radiation, it is desirable to develop non-ionising imaging procedures for the analysis of skeletal maturation for forensic age diagnostics in living individuals. The present pilot study analyses the applicability of ultrasound examinations for the evaluation of apophyseal ossification of the iliac crest. With reference to the sonographic staging of clavicular ossification, the maturation stages of the iliac crest apophysis of 23 male and 16 female subjects, aged 11-20 years, were determined. Ossification stage I occurred in the male subjects at a minimum age of 15.7 years. Ossification stage II was diagnosed in boys at a minimum age of 14.1 years and in girls at a minimum age of 11.7 years. The earliest observation of ossification stage III was at a chronological age of 16.2 years in males and 15.2 years in females. The earliest age of occurrence of ossification stage IV was at least 18.0 years in male test persons and at least 17.1 years in female test persons. The results obtained should be reassessed in a larger number of cases. It is to be expected that sonographic examination of the iliac crest apophysis will become established as a valid and efficient method for forensic age diagnostics in living individuals.

Odontometric sex assessment from logistic regression analysis

Abstract: Odontometric sex assessment is considered a useful adjunct to more robust predictors such as pelvic and cranial bones, and discriminant function analysis (DA) has been widely applied in dental sex assessment. Logistic regression analysis (LRA) is considered a better alternative, although still untested in odontometric sex prediction. This study examines the use of LRA in dental sex assessment and compares its success to DA. Mesiodistal and buccolingual dimensions of all teeth, except third molars, were obtained on dental stone casts of 105 young adults (52 females, 53 males) using digital caliper. Application of LRA to teeth of both jaws combined and to maxillary and mandibular teeth separately yielded correct sex allocation rates ranging from 76% to 100%, which proved superior to sex assessment using DA (∼52–71%). LRA enabled optimal sex prediction (100%) when all teeth in both the jaws were included. Results were not as accurate when only maxillary (76.2%) or mandibular (84.8%) teeth were used. To assess and compare the use of these multivariate techniques in practical forensic casework, >25% of tooth variables were randomly deleted. LRA still performed better (∼91% sex allocation accuracy vs. 62.9% for DA), indicating that LRA may be superior in its ability to predict sex irrespective of the presence of complete or incomplete sets of dentitions and should be preferred in dental sex assessment. The 100% success rate of LRA in correctly assigning sex is also noteworthy considering that, in general, tooth measurements have yielded sub-optimal sex prediction levels. However, unambiguous sex assessment is possible only when the entire dentition is available and correct sex allocation levels decreases when teeth are missing.

Disorders of glucose metabolism: post mortem analyses in forensic cases-part II

Abstract: In continuation to part I, a literature review is presented concerning biochemical problems of forensic post mortem cases of unclear hyperglycaemia or hypoglycaemia. Clinical parameters for this purpose were recently reviewed. Particular attention was paid to the detection of diabetic ketoacidosis, of hyperosmolar coma, insulinoma, insulin-induced or oral diabetic-induced hypoglycaemia. The second part of the review discusses the analytes ketone bodies, synthetic insulins, human insulin, C-peptide, proinsulin and insulin antibodies. Special interest is given to post mortem matrices for those analytes to reference concentrations, stability data, analytic interferences and analytical procedures which should be used in toxicological laboratories willing to detect diabetic metabolism disorders after death.

Postmortem biochemistry and immunohistochemistry of chromogranin A as a stress marker with special regard to fatal hypothermia and hyperthermia

Abstract: Chromoganin A (CgA) is widely distributed in the secretory granules of endocrine and neuroendocrine cells and cosecreted with hormones such as catecholamines. The present study investigated postmortem serum and cerebrospinal fluid (CSF) levels of CgA in comparison with those of catecholamines, and also cellular CgA immunopositivity in the hypothalamus, adenohypophysis and adrenal medulla to assess forensic pathological significance. Serial medicolegal autopsy cases (n = 298, within 3 days postmortem) were used. Serum and CSF CgA levels were independent of the gender or age of subjects or postmortem time. The most characteristic findings were seen for fatal hypothermia (cold exposure), hyperthermia (heat stroke) and intoxication. Serum CgA levels were lower for hypothermia and intoxication than for other causes of death (p < 0.05), while CSF CgA levels were higher for hypothermia (p < 0.0001). A negative correlation was detected between serum and CSF CgA levels for hypothermia (R = 0.552, p < 0.05). Correlations between serum levels of CgA and catecholamines (adrenaline, noradrenaline and dopamine) were evident for hyperthermia (R = 0.632–0.757, p < 0.05 to <0.01), but there was no significant correlation between CgA and catecholamine levels in CSF. Cellular CgA immunopositivity in the hypothalamus, adenohypophysis and adrenal medulla varied extensively among cases in each group. However, CgA immunopositivity in hypothalamus neurons was lower for hypothermia than other causes of death including hyperthermia and intoxication. These observations suggest characterictic neuroendocrinal activation in fatal cases of hypo- and hyperthermia and also intoxication. CgA may be a useful biochemical and immunohistochemical marker for investigating these causes of death.

Assessment of DNA degradation and the genotyping success of highly degraded samples.

Abstract: DNA becomes progressively more fragmented as biological tissue degrades resulting in decreasing ability to gain a complete DNA profile. Successful identification of samples exhibiting very high levels of DNA degradation may be complicated by presenting in minute quantities. The industry standard method for human DNA identification utilising short tandem repeats (STR) may produce partial or no DNA profile with such samples. We report a comparative study of genotyping using STRs, mini-STRs and single nucleotide polymorphisms (SNPs) with template at different levels of degradation in varying amounts. Two methods of assessing quantity and quality of a DNA sample prior to genotyping were investigated. The QIAxcel capillary gel electrophoresis system provided a rapid, cost effective screening method for assessing sample quality. A real-time quantitative PCR (qPCR) assay was able to simultaneously quantify total human DNA, male DNA, DNA degradation and PCR inhibition. The extent of DNA degradation could be assessed with reasonable accuracy to 62.5 pg and genomic targets could be quantified to a lower limit of 15.6 pg. The qPCR assay was able to detect male DNA to a lower limit of 20 pg in a 1:1,000 background of female DNA. By considering the amount of DNA and the degradation ratio of a sample, a general prediction of genotyping success using AmpFlSTR® Profiler Plus®, MiniFiler™ kits and SNP analysis can be made. The results indicate mini-STRs and SNP markers are usually more successful in typing degraded samples and in cases of extreme DNA degradation (≤200 bp) and template amounts below 250 pg, mini-STR and SNP analysis yielded significantly more complete profiles and lower match probabilities than corresponding STR profiles.

Estimation of the firing distance through micro-CT analysis of gunshot wounds.

Abstract: Estimation of the firing range is often critical for reconstructing gunshot fatalities, where the main measurable evidence is the gunshot residue (GSR). In the present study intermediate-range gunshot wounds have been analysed by means of a micro-computed tomography (micro-CT) coupled to an image analysis software in order to quantify the powder particles and to determine the firing distance. A total of 50 shootings were performed on skin sections obtained from human legs surgically amputated for medical reasons. For each tested distance (5, 15, 23, 30 and 40 cm), firing was carried out perpendicularly at the samples using a 7.65-mm pistol loaded with jacketed bullets. Uninjured skin sections were used as controls. By increasing the firing distance, micro-CT analysis demonstrated a clear decreasing trend in the mean GSR percentage, particularly for shots fired from more than 15 cm. For distances under 23 cm, the powder particles were concentrated on the epidermis and dermis around the hole, and inside the cavity; while, at greater distances, they were deposited only on the skin surface. Statistical analysis showed a nonlinear relationship between the amount of GSR deposits and the firing range, well explained by a Gaussian-like function. The proposed method allowed a good discrimination for all the tested distances, proving to be an objective, rapid and inexpensive tool for estimating the firing range in intermediate-range gunshot wounds.

State-of-the-art of bone marrow analysis in forensic toxicology: a review.

Abstract: Although blood is the reference medium in the field of forensic toxicology, alternative matrices are required in case of limited, unavailable or unusable blood samples. The present review investigated the suitability of bone marrow (BM) as an alternative matrix to characterize xenobiotic consumption and its influence on the occurrence of death. Basic data on BM physiology are reported in order to highlight the specificities of this matrix and their analytical and toxicokinetic consequences. A review of case reports, animal and human studies involving BM sample analysis focuses on the various parameters of interpretation of toxicological results: analytic limits, sampling location, pharmacokinetics, blood/BM concentration correlation, stability and postmortem redistribution. Tables summarizing the analytical conditions and quantification of 45 compounds from BM samples provide a useful tool for toxicologists. A specific section devoted to ethanol shows that, despite successful quantification, interpretation is highly dependent on postmortem interval. In conclusion, BM is an interesting alternative matrix, and further experimental data and validated assays are required to confirm its great potential relevance in forensic toxicology.

A sensitive method to extract DNA from biological traces present on ammunition for the purpose of genetic profiling

Abstract: Exploring technological limits is a common practice in forensic DNA research. Reliable genetic profiling based on only a few cells isolated from trace material retrieved from a crime scene is nowadays more and more the rule rather than the exception. On many crime scenes, cartridges, bullets, and casings (jointly abbreviated as CBCs) are regularly found, and even after firing, these potentially carry trace amounts of biological material. Since 2003, the Forensic Laboratory for DNA Research is routinely involved in the forensic investigation of CBCs in the Netherlands. Reliable DNA profiles were frequently obtained from CBCs and used to match suspects, victims, or other crime scene-related DNA traces. In this paper, we describe the sensitive method developed by us to extract DNA from CBCs. Using PCR-based genotyping of autosomal short tandem repeats, we were able to obtain reliable and reproducible DNA profiles in 163 out of 616 criminal cases (26.5%) and in 283 out of 4,085 individual CBC items (6.9%) during the period January 2003–December 2009. We discuss practical aspects of the method and the sometimes unexpected effects of using cell lysis buffer on the subsequent investigation of striation patterns on CBCs.

Chronological age estimation based on third molar development in a Portuguese population.

Abstract: Third molar development was assessed using a sample of 1,131 orthopantomograms from a Portuguese population. The methodology applied was the eight stages (A–H) method described by Demirjian et al. The final sample was made of 739 orthopantomograms, 387 (52.5%) of which belonging to females; age ranged between 6.1 and 22.5 years old (mean age = 14.49, S.D. = 4.37). For each developmental stage, mean age, standard deviation, and minimal and maximal age was assessed; evaluation of the rate formation of each tooth, according to sex, was calculated and data distribution expressed in percentiles for each stage; the probability of an individual being 16 was also evaluated. The relationship between tooth development and chronological age had a statistical significance for all teeth and both sexes (p < 0.0001). The data described may provide reference for forensic application and agree with the thesis that each population need specific data.

Estimating time of death based on the biological clock.

Abstract: The biological clock may stop at the time of death in a dead body. Therefore, the biological clock seems useful for estimating the time of death. In this study, we tried to read the biological clock in tissues from dead bodies to estimate the time of death using molecular biological techniques. At first, we examined real-time RT-PCR analysis of gene expression for mPer2 and mBmal1, which constitutes a feedback loop in the oscillation system, in the kidney, liver, and heart of mice. We could detect circadian oscillation of these gene expressions in mouse tissues even at 50 indicated the time of death as 0200–0900 hours, and a hRev/hBmal1 ratio that considerably exceeded 75 indicated the time of death as 0200–0800 hours. On the other hand, a hRev/hBmal1 ratio of less than 25 strongly indicated the time of death as 1000–2300 hours. Taken together, these findings indicate that gene expression analyses of the biological clock could be powerful methods for estimation of the time of death.

A new atlas for the evaluation of facial features: advantages, limits, and applicability

Abstract: Methods for the verification of the identity of offenders in cases involving video-surveillance images in criminal investigation events are currently under scrutiny by several forensic experts around the globe. The anthroposcopic, or morphological, approach based on facial features is the most frequently used by international forensic experts. However, a specific set of applicable features has not yet been agreed on by the experts. Furthermore, population frequencies of such features have not been recorded, and only few validation tests have been published. To combat and prevent crime in Europe, the European Commission funded an extensive research project dedicated to the optimization of methods for facial identification of persons on photographs. Within this research project, standardized photographs of 900 males between 20 and 31 years of age from Germany, Italy, and Lithuania were acquired. Based on these photographs, 43 facial features were described and evaluated in detail. These efforts led to the development of a new model of a morphologic atlas, called DMV atlas (“Dusseldorf Milan Vilnius,” from the participating cities). This study is the first attempt at verifying the feasibility of this atlas as a preliminary step to personal identification by exploring the intra- and interobserver error. The analysis yielded mismatch percentages from 19% to 39%, which reflect the subjectivity of the approach and suggest caution in verifying personal identity only from the classification of facial features. Nonetheless, the use of the atlas leads to a significant improvement of consistency in the evaluation.

Genetic analysis of sudden cardiac death victims : a survey of current forensic autopsy practices

Abstract: Autopsy-negative sudden cardiac deaths (SCD) seen in forensic practice are most often thought to be the result of sudden arrhythmic death syndrome. Postmortem genetic analysis is recommended in such cases, but is currently performed in only a few academic centers. In order to determine actual current practice, an on-line questionnaire was sent by e-mail to members of various forensic medical associations. The questions addressed routine procedures employed in cases of sudden cardiac death (autopsy ordering, macroscopic and microscopic cardiac examination, conduction tissue examination, immunohistochemistry and electron microscopy, biochemical markers, sampling and storage of material for genetic analyses, toxicological analyses, and molecular autopsy). Some questions concerned the legal and ethical aspects of genetic analyses in postmortem examinations, as well as any existing multidisciplinary collaborations in SCD cases. There were 97 respondents, mostly from European countries. Genetic testing in cases of sudden cardiac death is rarely practiced in routine forensic investigation. Approximately 60% of respondents reported not having the means to perform genetic postmortem testing and 40% do not collect adequate material to perform these investigations at a later date, despite working at university hospitals. The survey demonstrated that many of the problems involved in the adequate investigation of SCD cases are often financial in origin, due to the fact that activities in forensic medicine are often paid by and dependent on the judicial authorities. Problems also exist concerning the contact with family members and/or the family doctor, as well as the often-nonexistent collaboration with others clinicians with special expertise beneficial in the investigation of SCD cases, such as cardiologists and geneticists. This study highlights the importance in establishing guidelines for molecular autopsies in forensic medicine.

PopAffiliator: online calculator for individual affiliation to a major population group based on 17 autosomal short tandem repeat genotype profile.

Abstract: Because of their sensitivity and high level of discrimination, short tandem repeat (STR) maker systems are currently the method of choice in routine forensic casework and data banking, usually in multiplexes up to 15-17 loci. Constraints related to sample amount and quality, frequently encountered in forensic casework, will not allow to change this picture in the near future, notwithstanding the technological developments. In this study, we present a free online calculator named PopAffiliator ( http://cracs.fc.up.pt/popaffiliator ) for individual population affiliation in the three main population groups, Eurasian, East Asian and sub-Saharan African, based on genotype profiles for the common set of STRs used in forensics. This calculator performs affiliation based on a model constructed using machine learning techniques. The model was constructed using a data set of approximately fifteen thousand individuals collected for this work. The accuracy of individual population affiliation is approximately 86%, showing that the common set of STRs routinely used in forensics provide a considerable amount of information for population assignment, in addition to being excellent for individual identification.

Characteristics of eight X-STR loci for forensic purposes in the Chinese population

Abstract: X-chromosomal short tandem repeats (ChrX STRs) loci are used for forensic practice in recent years. Considering the unique heredity characteristics of ChrX, recombination and linkage disequilibrium (LD) among ChrX STR loci vary between male and female and different populations as well. However, there is a lack of data for analysis of recombination and linkage disequilibrium on ChrX STR loci in the Chinese population. In this work, a total of 303 unrelated individuals (203 males and 100 females) in the Chinese Han population were analyzed with Mentype Argus X-8 PCR amplification kit (DXS10135-DXS8378, DXS7132-DXS10074, HPRTB-DXS10101, and DXS10134-DXS7423). The recombination and linkage disequilibrium of the eight ChrX STR loci were investigated with HapMap LD plots and software ARLEQUIN 3.1. Allele frequencies of the eight loci and further population forensic genetic parameters were obtained. Our results revealed hotspots for recombination, and there was no obvious evidence for LD among the eight loci in the Chinese population. Our work implied that single locus frequencies rather than haplotype frequencies should be applied for forensic practice in the Chinese population.

Genetic diversities of 21 non-CODIS autosomal STRs of a Chinese Tibetan ethnic minority group in Lhasa

Abstract: In the present study, we investigated 21 short tandem repeat (STR) loci (D6S474, D12ATA63, D22S1045, D10S1248, D1S1677, D11S4463, D1S1627, D3S4529, D2S441, D6S1017, D4S2408, D19S433, D17S1301, D1GATA113, D18S853, D20S482, D14S1434, D9S1122, D2S1776, D10S1435, D5S2500), which are not included in the Combined DNA Index System and Amelogenin locus in 104 randomly selected healthy autochthonous individuals from the Tibetan ethnic minority group residing in the Lhasa region, Tibet Autonomous Region of China. Allelic frequencies, common forensic statistical parameters, and the Hardy–Weinberg equilibrium in this population were calculated with a modified PowerState V12.xls. A total of 143 alleles were found in the Tibetan group with corresponding allelic frequencies ranging from 0.005 to 0.582. The observed heterozygosity, the expected heterozygosity, the power of discrimination, the power of exclusion, and the polymorphic information content ranged from 0.615 to 0.817, 0.559 to 0.787, 0.727 to 0.926, 0.310 to 0.632, and 0.488 to 0.760, respectively. Chi-square tests of the observed genotype frequencies and expected genotype frequencies in the samples showed no departure from the Hardy–Weinberg equilibrium at all loci except for D5S2500. Our results demonstrate that these 21 STRs are highly polymorphic and suitable for anthropological research, population genetics, and forensic paternity testing and human individual identification in this region, and can enrich Chinese ethnical genetic informational resources.

An efficient multiplex genotyping approach for detecting the major worldwide human Y-chromosome haplogroups

Abstract: The Y chromosome is paternally inherited and therefore serves as an evolutionary marker of patrilineal descent. Worldwide DNA variation within the non-recombining portion of the Y chromosome can be represented as a monophyletic phylogenetic tree in which the branches (haplogroups) are defined by at least one SNP. Previous human population genetics research has produced a wealth of knowledge about the worldwide distribution of Y-SNP haplogroups. Here, we apply previous and very recent knowledge on the Y-SNP phylogeny and Y-haplogroup distribution by introducing two multiplex genotyping assays that allow for the hierarchical detection of 28 Y-SNPs defining the major worldwide Y haplogroups. PCR amplicons were kept small to make the method sensitive and thereby applicable to DNA of limited amount and/or quality such as in forensic settings. These Y-SNP assays thus form a valuable tool for researchers in the fields of forensic genetics and genetic anthropology to infer a man's patrilineal bio-geographic ancestry from DNA.

Forensic and genetic characterization of mtDNA from Pathans of Pakistan

Abstract: Complete mitochondrial control region data were generated for 230 unrelated Pathans from North West Frontier Province and Federally Administered Tribal Areas of Pakistan. To confirm data quality and to explore the genetic structure of Pathans, mitochondrial DNA haplogroup affiliation was determined by shared haplogroup-specific polymorphisms in the control region and by the analysis of diagnostic coding region single-nucleotide polymorphisms using a multiplex system for the assignment of eight haplogroups: M, N1′5, W, R, R0, T, J, and U. Sequence comparison revealed that 193 haplotypes were defined by 215 variable sites when major insertions were ignored at nucleotide positions 16193, 309, and 573. From a phylogenetic perspective, Pathans have a heterogeneous origin, displaying a high percentage of West Eurasian haplogroups followed by haplogroups native to South Asia and a small fraction from East Asian lineages. In population comparisons, this ethnic group differed significantly from several other ethnic groups from Pakistan and surrounding countries. These results suggest that frequency estimates for mtDNA haplotypes should be determined for endogamous ethnic groups individually instead of pooling data for these subpopulations into a single dataset for the Pakistani population. Data presented here may contribute to the accuracy of forensic mtDNA comparisons in the Pathans of Pakistan.

Sex estimation of the Cretan humerus: a digital radiometric study

Abstract: Sex estimation based on measurements of unidentified skeletal remains recovered in crime and death scenes can be accomplished with accuracy. In mass disasters, however, the remains are often fleshed, burned, and/or commingled. As a result, osteometric methods are difficult to apply. In such cases, radiography can be of great use during the examination process. A total of 101 (53 males and 48 females) adult humeri were radiographed using digital equipment (Technix TCA 4R PLUS). Specific measurements were taken on the radiographs and then analyzed. Multivariate discriminant function analysis was applied, and the results showed up to 89.1% classification accuracy. Single variables performed equally well for both epiphyses reaching 86.1% correct group membership. The method proposed here is successful, offering an alternative sex estimation technique applicable to the identification of deceased individuals whose remains are semi-fleshed, burned, mutilated, or otherwise unrecognizable. Specifically, this method is extremely useful when maceration of the remains is not an option.

Deaths involving contraindicated and inappropriate combinations of serotonergic drugs

Abstract: In the Australian state of Victoria, all fatalities that were recorded from 2002 through to 2008 involving the use of certain serotonin active drugs (tramadol, venlafaxine, fluoxetine, sertraline, citalopram and paroxetine), were reviewed to assess the incidence of contraindicated or ill advised drug combinations. More than 1,000 were identified of which 326 cases formed the basis of this study. These cases involved contraindicated or inappropriate drug combinations that can lead to adverse drug reactions (ADRs) and subsequent fatal toxicity. Of these, 46% were drug-related, 35% were a result of natural disease and 13% were classified as external injury cases. The remaining cases were those where the cause of death (COD) was unascertained. Tramadol was the most common drug, usually detected alongside a serotonergic antidepressant (in 20% of cases). Twenty-five (8%) cases involved contraindicated drug combinations while the remainder (301 cases, 92%) involved drug combinations that are associated with adverse interactions ranging from minor to major severity. Of these 326 cases, the Coroner determined 166 cases (51%) to be acts of intentional self-harm or drug misuse, with the remainder unascertained or attributed to natural disease. Very few post-mortem reports and Coroners’ findings made mention of possible ADRs when such combinations were actually present. The majority of cases comprising contraindicated drug combinations involved the combined use of five drugs (24%) at the time of death. A combination of three to five drugs was most common in cases involving inadvisable drug combinations. Combined drug toxicity was the most common COD, with heart disease the most common co-morbidity.

Software for Y-haplogroup predictions: a word of caution

Abstract: The development of online software designed for genetic studies has been exponentially growing, providing numerous benefits to the scientific community. However, they should be used with care, since some require adjustments. The efficiency of two programs for haplogroup prediction was tested with 119 samples of known haplotypes and haplogroups from Argentine populations. Quantitative estimates of the predictive quality of both software systems were computed with the uncertainty coefficient; and sensitivity, specificity, positive, and negative likelihood ratios were also calculated to assert the reliability of both programs, showing high probabilities of assigning an incorrect haplogroup.

Allele and haplotype diversity of X-chromosomal STRs in Ivory Coast

Abstract: Twenty-one X-chromosomal short tandem repeat (STR) loci, including the six clusters of linked markers DXS10148–DXS10135–DXS8378 (Xp22), DXS7132–DXS10079–DXS10074 (Xq12), DXS6801–DXS6809–DXS6789 (Xq21), DXS7424–DXS101 (Xq22), DXS10103–HPRTB–DXS10101 (Xq26), DXS8377–DXS10146–DXS10134–DXS7423 (Xq28) and the loci DXS6800, GATA172D05 and DXS10011 were typed in a popula3tion sample from Ivory Coast (n = 125; 51 men and 74 women). Allele and haplotype frequencies as well as linkage disequilibrium data for kinship calculations are provided. On the whole, no significant differences in the genetic variability of X-STR markers were observed between Ivorians and other sub-Saharan African populations belonging to the Niger–Kordofanian linguistic group.

Similarity and match rates of the human dentition in three dimensions: relevance to bitemark analysis

Abstract: Uniqueness of the human dentition is a fundamental premise in bitemark analysis. Despite the importance of this key aspect of bitemark methodology, systematic studies of large populations have been limited. Furthermore, there have been no investigations of the significance of the third dimension with regard to dental uniqueness. One hundred digitally scanned mandibular models were analyzed in both 2D and three dimension (3D) using Landmark software. Additionally, 500 3D maxillary and mandibular sets were investigated for determining dental match rate. Statistical analysis was performed with geometric morphometric methods. Results show that measurements in 3D preserve more information about the dentition, reducing but not eliminating random matches in a sample population of 100 mandibular dentitions. Examination of pairs of maxillary and mandibular dentitions showed a substantial number of random matches (197 maxillary, 51 mandibular, one of both maxillary and mandibular). Conclusions indicate that a zero match rate cannot be claimed for the population studied.