Photo identification: facial metrical and morphological features in South African males

Personal identification of individuals is very important in forensic sciences. Facial identification is becoming even more relevant with increasing crime rates, problems with access control and terrorist attacks. To make facial identification more accurate, an in depth knowledge of the common and rare facial characteristics seen in various populations is needed. This will be advantageous when comparing facial photographs. Currently very little data is available on the facial variation of South Africans. Therefore the aim of this study was to analyse the facial features of a group of South African Bantu-speaking men, to determine the common and rare facial features seen in the group. Facial photographs were taken for 200 volunteers from the Pretoria Police College, in the norma frontalis position. The subjects were between 20 and 40 years of age, with no facial deformities. Thirteen measurements were taken directly from the photographs and used in 12 indices. Eight morphological features were also analysed on each face. Each feature was divided into different categories, which described variants of that feature. The metrical and morphological data were then used to create various combinations of facial characteristics that described different regions of the face. The frequency of occurrence of these combinations was calculated for the study population. The most common features were oval or inverted trapezoid facial shapes, intermediate size noses with a down-turned septum tilt and intermediate size mouths with a flat V-shaped upper lip notch (cupid's bow). The eyes were mostly situated closely together. Some of the rare or absent features included round or square facial shapes and narrow noses with an upturned septum tilt. Matching these rare features on facial photographs will be useful during cases of disputed identification.     

Investigating the morphology and genetics of scalp and facial hair characteristics for phenotype prediction

Microscopic traits and ultrastructure of hair such as cross-sectional shape, pigmentation, curvature, and internal structure help determine the level of variations between and across human populations. Apart from cosmetics and anthropological applications, such as determining species, somatic origin (body area), and biogeographic ancestry, the evidential value of hair has increased with rapid progression in the area of forensic DNA phenotyping (FDP). Individuals differ in the features of their scalp hair (greying, shape, colour, balding, thickness, and density) and facial hair (eyebrow thickness, monobrow, and beard thickness) features. Scalp and facial hair characteristics are genetically controlled and lead to visible inter-individual variations within and among populations of various ethnic origins. Hence, these characteristics can be exploited and made more inclusive in FDP, thereby leading to more comprehensive, accurate, and robust prediction models for forensic purposes. The present article focuses on understanding the genetics of scalp and facial hair characteristics with the goal to develop a more inclusive approach to better understand hair biology by integrating hair microscopy with genetics for genotype-phenotype correlation research.     

A multivariate statistical approach to for the evaluation of the biogeographical ancestry information from traditional STRs

The capability to achieve biogeographic ancestry (BGA) information from DNA profiles have been largely explored in forensic genetics because of its potential usefulness in providing investigative clues. For law enforcement and security purposes, when genetic data have been obtained from unknown evidence, but no reference samples are available and no hints come out from DNA databases, it would be extremely useful at least to infer the ethno-geographic origin of the stain donor by just examining traditional STRs DNA profiles.Current protocols for ethnic origin estimation using STRs profiles are usually based on Principal Component Analysis approaches and Bayesian methods. The present study provides an alternative approach that involves the use of target multivariate data analysis strategies for estimation of the BGA information from unknown biological traces. A powerful multivariate technique such as Partial Least Squares-Discriminant Analysis (PLS-DA) has been applied on NIST U.S. population datasets containing, for instance, the allele frequencies of African-American, Asian, Caucasian and Hispanic individuals. PLS-DA approach provided robust classifications, yielding high sensitivity and specificity models capable of discriminating the populations on ethnic basis. Finally, a real casework has been examined by extending the developed model to smaller and more geographically-restricted populations involving, for instance, Albanian, Italian and Montenegrian individuals.     

Metric characterization of the human coxal bone on a recent Italian sample and multivariate discriminant analysis to determine sex

The ability of human pelvic bones to sexually differentiate has been of great interest in forensic anthropology for quite some time as it allows for the determination of skeletal sex by combining metric and morphological data. However, the criteria for determining the sex of a skeleton must be calibrated according to the variability of the population to which it belongs. The aim of this work is the metric characterization of the human coxal bone on a recent sample (of known sex) from the region of Apulia, in southern Italy, in order to establish its efficacy in sex determination by way of multivariate discriminant analysis. Seventeen standard anthropological measurements used in sex determination were taken from 168 coxal bones (78 males and 90 females) all belonging to 86 adult skeletons (40 males and 46 females). The bones used were taken from subjects who had died in the 1960s and 1970s in Apulia. The results obtained define the variability in size and proportion of the sample analyzed with respect to the variations of other skeletal populations. Nine discriminant functions, utilizing between 4 and 11 variables, have been shown to be useful in determining the sex of coxal bones, whether they be complete, partial, or fragmented. All of the functions selected resulted in an attribution error equal to zero, and differ only in the number of variables utilized and by the degree of separation between the groups. The results of this study confirm the validity and utility of diagnostic techniques based on discriminant functions as reported in the literature for other population groups. The combination of metric characteristics from various regions of the coxal bone is, therefore, a valid aid in the correct attribution of skeletal sex even when the combination of variables is numerically limited, but sufficient in sex determination from partial coxal bones.     

人类D19S40基因座在不同人种中的遗传多态性研究

采用ＰＣＲ技术分析中国汉族、德国人、斯洛伐克人和美国黑人群体Ｄ１９Ｓ４００基因座的遗传多态性及世界三大人种之间的差异。四个群体共调查了６２０人,发现了１１个等位基因,观察到４７种基因型。各群体观察杂合度为：０．７８～０．８８,个人识别机率为：０．９３８５０～０．９６６４。四个群体基因型频率分布符合Ｈａｒｄｙ－Ｗｅｉｎｂｅｒｇ平衡（Ｐ＞０．０５）,三大人种（蒙古人种、高加索人种、美国黑人）之间Ｄ１９Ｓ４００基因座等位基因频率分布存在极显著差异（Ｐ＜０．０１）。结果显示Ｄ１９Ｓ４００基因座在群体遗传学研究和法医学个人识别中有较高应用价值     

A new method for the evaluation of matches in non-recombining genomes: application to Y-chromosomal short tandem repeat (STR) haplotypes in European males

A 9-locus microsatellite framework (minimal haplotype), previously developed for forensic purposes so as to facilitate stain analysis, personal identification and kinship testing, has been adopted for the establishment of a large reference database of male European Y-chromosomal haplotypes. The extent of population stratification pertaining to this database, an issue crucial for its practical forensic application, was assessed through analysis of molecular variance (AMOVA) of the 20 regional samples included. Despite the notion of some significant haplotype frequency differences, which were found to correlate with known demographic and historic features of Europeans, AMOVA generally revealed a high level of genetic homogeneity among the populations analyzed. Owing to their high diversity, however, accurate frequency estimation is difficult for Y-STR haplotypes when realistic (i.e. moderately sized) datasets are being used. As expected, strong pair-wise and higher order allelic associations were found to exist between all markers studied, implying that haplotype frequencies cannot be estimated as products of allele frequencies. A new extrapolation method was therefore developed which treats haplotype frequencies as random variables and generates estimates of the underlying distribution functions on the basis of closely related haplotypes. This approach, termed frequency 'surveying', is based upon standard population genetics theory and can in principle be applied to any combination of markers located on the Y-chromosome or in the mitochondrial genome. Application of the method to the quality assured reference Y-STR haplotype database described herein will prove very useful for the evaluation of positive trace-donor matches in forensic casework.     

Forensic genetic value of 27 Y-STR loci (Y-Filer® Plus) in the South African population

South Africa has one of the highest rape statistics in the world, with an average of 117 rapes reported daily. Y-STR genotyping is becoming a popular tool in the analysis of DNA evidence collected after a crime of a sexual nature has been committed, but has yet to be implemented in South Africa’s forensic laboratories. This study aimed to investigate the forensic value of the 27 Yfiler™ Plus loci in the South African population. A total of 271 samples from the African, Asian/Indian, Mixed Ancestry¹, and Caucasian populations at the University of the Free State in Bloemfontein, South Africa were amplified and analysed using ThermoFisher Scientific’s Yfiler™ Plus PCR Amplification kit. Of the 271 samples, 261 were identified to be unique, with an overall discrimination capacity of 98.15%. Discrimination capacities ranged from 91.67% for the Asian/Indian population to 100% for the Mixed Ancestry population. The haplotype diversity across the four populations is 0.9999, with an average gene diversity across all loci of 0.717. The forensic parameters estimated in this study provide evidence for the potential use of the commercial Yfiler™ Plus PCR amplification kit in a forensic application in South Africa.     

Comparison of methods to determine sex by evaluating the greater sciatic notch: Visual, angular and geometric morphometrics

Sex estimation is the first step for biological profile reconstruction of an unknown skeleton (archaeological or contemporary) and consequently for positive identification of skeletal remains recovered from forensic settings. Several tools have been developed using different osseous structures. With the intention to provide an objective method comparison, we reported the analysis of three different methods (visual, metric and geometric morphometrics) for sex assessment of the greater sciatic notch. One hundred and thirty pelvic bones (45.4% females and 54.6% males) from the National Autonomous University of Mexico Skeletal Collection pertaining to the contemporary Mexican population were analyzed. We used the ROC-analysis to test between desired false positive thresholds (1-specificity) and expected true positive rates (sensitivity) in order to predict the best approach to sex assessment. The comparison of the area under the ROC-curves shows significant differences among visual and metric methods. At the same time, the analysis suggested that higher morphological variation among the sexes is independent of the methodological approach. The results indicate that the metric (angle), with a high percent of indeterminate cases (34.6%), and visual, with 26.2% of the cases allocated as intermediate cases, were poorly accurate; we cannot recommend these techniques for sexing an unknown specimen. On the other hand, the geometric morphometrics approach improves sex estimation in 82.3% of correctly classified individuals with more than 95% of posterior probability. In addition to the method comparison, the major sexual variation of the greater sciatic notch was determined to be located on its posterior border.     

Forensic Facial Reconstruction: Relationship Between the Alar Cartilage and Piriform Aperture

During forensic facial reconstruction, facial features may be predicted based on the parameters of the skull. This study evaluated the relationships between alar cartilage and piriform aperture and nose morphology and facial typology. Ninety‐six cone beam computed tomography images of Brazilian subjects (49 males and 47 females) were used in this study. OsiriX software was used to perform the following measurements: nasal width, distance between alar base insertion points, lower width of the piriform aperture, and upper width of the piriform aperture. Nasal width was associated with the lower width of the piriform aperture, sex, skeletal vertical pattern of the face, and age. The current study contributes to the improvement of forensic facial guides by identifying the relationships between the alar cartilages and characteristics of the biological profile of members of a population that has been little studied thus far.     

Implant Bone Integration Importance in Forensic Identification

Odontological identification consists of the comparison of antemortem dental information regarding a missing person with postmortem data from an unidentified corpse or human remains. Usually, the comparison concerns morphologic features that the operator chooses among all the visible characteristics because of inter‐individual uniqueness; for this reason, implants can be of enormous assistance. A case concerning the recovery of a burnt oral implant, connected to a bone fragment, among 2780 charred bone fragments, suspected to have belonged to a victim of homicide, is presented to demonstrate that dental implants and their site of bone integration represent a very precious element for personal forensic identification. Because of their morphological invariability in time and because of their morphologic uniqueness, they were used as evidence to associate unidentified human charred remains to a missing person where DNA analysis failed to do so. The case illustrates the fundamental contribution, not yet described in literature, given by the clinical aspects of tooth replacement with dental implants to a forensic discipline. Clinical practitioners should therefore be aware of the great importance of their work and of dental records in a forensic identification scenario.     

Assessing forensic applications of the frontal sinus in a Chinese Han population

The frontal sinus is an important tool of personal identification. To assess the forensic applications of the frontal sinus patterns in a Chinese Han population, 198 individuals were analyzed. 165 individuals who have the frontal sinus were observed in this population, and 12 parameters of the frontal sinus were observed according to Yoshino’s method. The same combined code was found in three persons from our samples. The unilateral frontal sinus scalloped with one arcade has few parameters applied to personal identification, and shows the poorer discrimination power. These parameters showed better discrimination power in our population, and could be applied to personal identification.     

Microscopical discrimination of human head hairs sharing a mitochondrial haplogroup

In forensic analyses, determining the level of consensus among examiners for hair comparison conclusions and ancestry identifications is important for assessing the scientific validity of microscopical hair examinations. Here, we present data from an interlaboratory study on the accuracy of microscopical hair comparisons among a subset of experienced hair examiners currently analyzing hair in forensic laboratories across the United States. We examined how well microscopical analysis of hair can reliably be used to differentiate hair samples, many of which were macroscopically similar. Using cut hair samples, many sharing similar macroscopic and microscopic features, collected from individuals who share the same mitochondrial haplogroup as an indication of genetic relatedness, we tested multiple aspects that could impact hair comparisons. This research tested the extent to which morphological features related to ancestry and hair length influence conclusions. Microscopical hair examinations yielded accurate assessments of inclusion/exclusion relative to the reference samples among 85% of the pairwise comparisons. We found shorter hairs had reduced levels of accuracy and hairs from populations examiners were not familiar with may have impacted their ability to resolve features. The reliability of ancestry determinations is not yet clear, but we found indications that the existing categories are only somewhat related to current ethnic and genetic variation. Our results provide support for the continued utility of microscopical comparison of hairs within forensic laboratories and to advocate for a combined analytical approach using both microscopical analysis and mtDNA data on all forensic analyses of hair.     

Positive Personal Identification of Human Remains Based on Thoracic VertebralMargin Morphology

Abstract: Radiography has long been used by anthropologists to establish positive personal identification of human remains in forensic cases. These methods have been largely ad hoc and depend upon specific congenital or pathological bone markers. Court rulings, such as Daubert and Mohan have, however, pushed the discipline toward more statistically supportable methods of identification. This study describes the use of normal morphological variation of the thoracic vertebrae to identify human remains. Radiographs from healthy, male individuals, aged 18–55 were examined to identify normally varying features of vertebral morphology. The frequency of occurrence of these features was calculated, tested, and found to be stable in the given sample. The frequencies were compared to establish which sets of traits varied independently of one another. Finally, unknown radiographs were compared to known samples to test the applicability of this method in determining positive identification, with 21 of 24 (87.5%) unknown radiographs positively identified.     

Spanish population data on seven loci: D1S80, D17S5, HUMTH01, HUMVWA,ACTBP2, D21S11 and HLA-DQA1

Blood samples from 120 Spanish Caucasian individuals were amplified and typed by electrophoresis at six loci, and by reverse dot-blot hybridization at one locus. Results demonstrate the assumption of independence within and between the seven loci analyzed. Therefore, a Spanish population database has been established and statistical analysis shows that a high degree of discrimination can be obtained when all seven (or fewer) loci are used to characterize forensic biological evidence.     

A proposed method for the identification of race in sub-adult skeletons: a geometric morphometric analysis of mandibular morphology

The identification of biological race (ancestry) in skeletal material is an important aspect of forensic investigations. While techniques for race determination are well established for adult skeletons, identification of race in sub-adult specimens has not been widely addressed. The present study investigates racial differences in the mandibular morphology of sub-adult specimens using geometric morphometric analyses. One hundred and seventy-four mandibles from five morphologically distinct samples were digitized and subjected to general Procrustes analysis. Results showed significant morphological differences between the samples and obtained cross-validation results of over 70% accuracy in identification of unknown individuals using the complete mandible. It is suggested that these techniques could provide a method for the identification of race in sub-adult individuals.     

Validation of chest X-ray comparisons for unknown decedent identification

Comparing skeletal structures between antemortem and postmortem chest radiographs is widely used by forensic specialists from many disciplines to positively identify unknown decedents. However, validity assessments of this method have been fairly limited. This study had three objectives: 1) to quantify the reliability of ante- and postmortem chest radiograph comparison for decedent identification; 2) to identify useful radiologic features supporting decedent identification; and 3) to recognize sources of error in decedent identification related to use of comparative radiographs. A forensic pathologist, a forensic anthropologist, and two radiologists participated in the study. Our results showed that chest radiograph comparisons proved reliable, if basic decedent information was provided, and antemortem and postmortem radiographs were adequately positioned and exposed. A "morphological approach" using normal anatomical structures for comparison may provide the most efficient method for accurate identification.     

Self-reported personality traits in forensic populations: a meta-analysis

The current study covers a systematic review and meta-analysis of the prevalence of self-reported deviant or disruptive personality traits: anger, aggression, hostility, antisocial traits, psychopathy, and impulsivity in forensic populations worldwide. A computer-based search of titles was carried out using the PubMed electronic database for articles published in English that included a self-report instrument for personality characteristics in combination with a forensic population (i.e. detained in remand, sentenced and/or in enforced treatment, or on parole). The final sample consisted of 39 studies (N?=?11,716) that together used 17 different instruments and reported on 32 subscales or constructs that fitted our current interest. Results showed significantly higher levels of self-reported antisocial and psychopathic features in forensic samples, including a significant effect of the assessment instrument and subscale used. No significant differences were found for self-reported impulsivity, anger, aggression, or hostility in forensic populations compared to norm scores of non-forensic samples. Possible explanations, including suggestions that forensic populations are prone to providing socially desirable answers on self-report questionnaires, possibly to gain advantages such as a lower prison sentence or to avoid enforced treatment, are discussed, as well as limitations, and suggestions for future research and clinical practice.     

Oral and skin microbiome as potential tools in forensic field

The interest in the analysis of the human microbiome for personal identification purposes is based on the microbial diversity amongst individuals. The oral cavity hosts one of the most diverse and abundant microbial communities in the human body; the skin instead is a complex living ecosystem with unique microbial niches at different sites. Both skin and oral microbiomes are highly individual and relatively stable over time. As saliva and skin debris are often found at crime scenes, the analysis of their microbiome may represent a potential tool for personal identification. However, there are some gaps in knowledge on how factors such as age, sex, geographic origin, diet and pathologies can affect the composition of the microbiome. The aim of this study is to improve the existing knowledge by examining oral and skin microbiomes from the same individuals and evaluating the variability between anatomical sites and donors. For this study, 50 individuals living in Italy donated oral swab samples and provided information regarding their diet, lifestyle, health status, antibiotic use, and other demographic data. Skin swabs from 11 of the 50 individuals were also analysed and compared to the oral swabs from the same donors. All analyses were done through metabarcoding of the 16S rRNA region of DNA extracted from the samples. This research outlines the potential use of oral and skin microbiome signatures as added evidence in personal identification, providing useful investigative clues for future forensic caseworks.     

Case report of a homicide resolved 15 years later: The robustness of Chelex extraction

DNA typing techniques is one of the most advanced tools for human identification. During the last 10 years, a great number of methods for DNA extraction and analysis have been introduced to forensic genetic, with considerable success but also with considerable controversy. The success and validation of a criminal investigation are very closely related to the process used for obtaining and preserving biological evidence.We report the strategy that we employed to analyze evidences belonging to a homicide happened in Brescia (Italy) in 1992, not resolved at that time, with the forensic genetic analysis. After 16 years the analysis were conducted on DNA samples extracted with Chelex maintained at −80 °C, bloodstain, and biological specimens of perpetrators. Standard autosomal and Y-chromosome STR analysis identified the persons involved and victim's profiles. This case is of interest as a demonstration of a more successful application of DNA typing in well conserved DNA samples than in bloodstains kept in the Court Office.