Applications of forensic anthropology methodology: accuracy of virtual face reproductions performed on the Tenchini collection.

Facial reproduction validation uses the methodology typical of forensic anthropology to confirm the accuracy of three-dimensional reproductions of faces. Achieving high accuracy in virtual facial reproductions is still under study. In the present paper, the Tenchini collection, which contains wax reproductions of prisoners' faces and their skulls, was used. By creating facial reproductions on skulls from this collection, the result was compared with the real face of the person to whom the skull belongs. The three-dimensional volume of each examined skull of Tenchini collection was acquired via CT scan and photogrammetry. Subsequently, the virtual reproduction of each skull was processed using three-dimensional graphics software (ZBrush, Pixologic®). The morphological comparison parameters used in the field of personal identification by forensic anthropology were used. The blind procedure required the operator to see the mask subsequent to the facial reproduction phase, so that the facial reproduction cannot exploit the information that knowledge of the mask would have produced. The parameters used in the study of facial reproductions have shown discrepancies between the characteristics of the masks and the facial reproductions, partly expected because due to the lack of soft tissue on the skull. However, a high degree of accuracy in the facial reproductions performed due to the applied methodology was documented. The present study allowed us to observe how these parameters can be useful to study the accuracy of facial reproduction and identify what difficulties are encountered in producing a result close to the real appearance.

The forensic imaging technique of age progression used within missing people cases: The Italian Missing Children association realizing age progression for Missing Child Kenya.

The age progression technique allows to update identification photos of individuals who have been missing for years. This method is based on the study of the facial variation and on the dynamics of facial growth. Knowledge about changes in the distribution of facial fat and the tone of the cartilage allows realistic predictions of the facial appearance after many years. Beside these elements, age progression is also supported by similar characters between family members. This is why photos of the missing and family members are used to create an age progression, making the new identikit accurate. Non-profit associations are crucial for the dissemination of information on the problem of missing persons. In Italy, the Italian Missing Children association provides for free an age progression service with the support of forensic anthropology. With the activation of a protocol, consisting of guidelines, and a form for the request for age progression by family members, the Italian Missing Children has started a collaboration with Missing Child Kenya. It allowed to disseminate up-to-date photos of the presumed current appearance of the missing children in Kenya. Thus, in the present study some cases are reported, in which age progression technique was applied. The photos provided by Italian Missing Children were shown in video documentaries made by Missing Child Kenya, allowing to continue the dissemination of age progression photo during the Covid quarantines and to keep the population active in the search for the missing.

Father figure: Study of the age progression process from old pictures and its value in forensic sciences.

The application of age progression to the search for missing persons demonstrates its usefulness in being able to reconstruct the aged face based on the current age of a person who has been missing for many years. Age progression takes into account facial physiognomic elements and their changes over time. Based on these premises, the present study aims to investigate the evolution of somatic features, from childhood to adulthood, of one of the authors' father using photos at different ages of him. Sixteen photos were collected depicting an individual of Italian origin between the age of 1 and 72. The photos were processed in Adobe© Photoshop software to graphically highlight the shape development of individual physiognomic elements. The shape of the face, eyebrows, eyes, nose, mouth, and cheeks were analysed in detail using a morphological approach. The ageing processes that occurred in this case were discussed on the basis of the literature. The present study demonstrates the in-depth analysis of the dynamics of facial growth in a single case. Nonetheless, aging is different for each individual, so further studies are necessary to observe facial development on as many subjects as possible.

Identification of a decedent in a 103-year-old homicide case using forensic anthropology and genetic genealogy.

Anthropologists are often the custodians of long-term unidentified human remains though their positions as curators of university or museum skeletal collections. Various factors decrease the solvability of these legacy cases including the passage of time, the loss of provenience for specific cases, and lack of documentation or case records. While anthropologists can contribute important information toward identification, it is often necessary to explore novel and cross-disciplinary strategies to resolve difficult cold cases. In long cold cases, the postmortem interval, in particular, may be difficult to estimate leading to further challenges in achieving identification. Modern advances in radiocarbon bomb pulse dating, isotope analysis, and actualistic studies have contributed to positive identification of unidentified human remains in some legacy cases, but may not be available to all forensic practitioners and law enforcement from resource-poor agencies. Pooling resources, as well as collaborating with professionals outside of forensic anthropology, is a useful strategy to pursue when anthropological methods are exhausted.The case study presented here demonstrates a collaborative approach between forensic anthropologists, forensic genetic genealogists, and law enforcement in a century-old homicide. The dismembered and mummified parts of a male body were recovered in a remote cave in 1979 and again in 1991. Despite forensic anthropologists creating and updating the biological profile over the decades from recovery to present, no identification was made until the application of forensic genetic genealogy (FGG) to the case in 2019. New interpretations of bone microstructure and trauma analysis are presented for the case, alongside the historical documentation and "proof of life" evidence used by the genealogy team. A review of the FGG methods underscores the challenges in this case (e.g. significant endogamy, multiple aliases used by the victim) and the steps taken toward resolution. Ultimately, a combined anthropology and genealogy approach resulted in a confirmed identity for a man who was murdered in 1916.Key pointsForensic scientists should leverage a collaborative, interdisciplinary approach toward human identification.When combined with forensic anthropology methods, forensic genetic genealogy is a valuable tool linking biological and cultural-historical aspects of identity.Forensic anthropologists should review challenging cases in their labs as new methods are introduced and new resources become available.

Purkait's triangle revisited: role in sex and ancestry estimation.

Identification of unknown remains recovered from marine and terrestrial locations is a significant humanitarian problem. This investigation proposes a simple method applicable to fragmentary femora for a more refined level of ancestry and/or sex estimation. To that end, we re-examined Purkait's triangle which involves three inter-landmark distances between the traction epiphyses and the articular rim of femoral head. A large sample (n = 584) from geographically diverse (Egyptian, Indian and Greek) populations was compiled. Additionally, shape (n = 3) and trigonometrically derived variables and ratios (n = 9 variables) were employed to detect any geographically-clustered morphological differences between these populations. Random forest modelling (RFM) and linear discriminant function analysis (LDA) were employed to create classification models in instances where sex was known or unknown. The sample was apportioned into training and test sets with a ratio 70/30. The classification accuracies were evaluated by means of k fold cross-validation procedure. In sex estimation, RFM showed similar performance to LDA. However, RFM outperformed LDA in ancestry estimation. Ancestry estimation was satisfactory in the Indian and Egyptian samples albeit the Greek sample was problematic. The Greek samples presented greater morphological overlap with the Indian sample due to high within-group variation. Test samples were accurately assigned to their ancestral category when sex was known. Generally, higher classification accuracies in the validation sample were obtained in the sex-specific model of females than in males. Using RFM and the linear variables, the overall accuracy reached 83% which is distributed as 95%, 71% and 86% for the Egyptian, Indian and Greek females, respectively; whereas in males, the overall accuracy is 72% and is distributed as 58%, 87% and 50% for the Egyptian, Indian and Greek males, respectively. Classification accuracies were also calculated per group in the test data using the 12 derived variables. For the females, the accuracies using the medians model was comparable to the linear model whereas in males the angles model outperformed the linear model for each group but with similar overall accuracy. The classification rates of male specific ancestry were 82%, 78% and 56% for the Egyptian, Indian and Greek males, respectively. In conclusion, Purkait's triangle has potential utility in ancestry and sex estimation albeit it is not possible to separate all groups successfully with the same efficiency. Intrapopulation variation may impact the accuracy of assigned group membership in forensic contexts. Key pointsPurkait's method is a possible ancestry group indicator applicable to fragmentary femora.Random forest model surpassed linear discriminant function analysis in multi-group ancestry classification.Ancestry is more accurately assessed in females than males.The intertrochanteric distance is the most important feature in discrimination of sex whereas in ancestry it was the head to lesser trochanter distance.Sex differences override ancestry due to the tendency of misclassification into same sex but different group rather than the opposite sex of the same ancestry.

Age estimation of individuals aged 5-23 years based on dental development of the Indonesian population.

Dental development can be used to estimate age for forensic purposes. However, most of the currently available methods are less reliable for the Indonesian population due to population variability. This study presents a new method and evaluates other methods that utilize dental development to estimate the age of Indonesian people. Panoramic radiographs of 304 young Indonesian people aged 5-23 years old were analysed for deciduous tooth root resorption, permanent tooth calcification, and eruption. The extent of tooth root resorption was determined based on AlQahtani's modified Moorrees et al. method. Tooth calcification was classified based on a modified Demirjian et al. method. Tooth eruption was evaluated based on AlQahtani's modified Bengston system. The sequence of tooth root resorption, and permanent tooth calcification and eruption were grouped into 19 age categories (from 5-23 years old) in an atlas. The differences between males and females, between maxillary and mandibular teeth, and between right and left teeth were also analysed. There were minimal significant differences of tooth development between males and females, and between the right and left teeth (P > 0.05), while the maxillary and mandibular dental development was significantly different (P < 0.05). The newly developed atlas showed the development of the right side of maxillary and mandibular tooth of combined sex of Indonesian population. Another 34 panoramic radiographs of known-age and sex individuals from Indonesia were assessed using the newly developed Atlas of Dental Development in the Indonesian Population, Ubelaker's Dental Development Chart, The London Atlas of Human Tooth Development and Eruption by AlQahtani, and the Age Estimation Guide-Modern Australia population by Blenkin-Taylor. Accuracy was assessed by comparing estimated age to actual chronological age using the Bland-Altmand test. Results show that the smallest range of error was found in the Atlas of Dental Development in the Indonesian Population (-0.969 to 1.210 years), followed by The London Atlas of Human Tooth Development and Eruption by AlQahtani (-2.013 to 1.990 years), the Age Estimation Guide-Modern Australia population by Blenkin-Taylor (-2.495 to 2.598 years), and the Dental Development Chart by Ubelaker (-2.960 to 3.289 years). These findings show that the Atlas of Dental Development constructed in this study performs better than the other three methods and presents greater accuracy of age estimation in the Indonesian population.Key pointsDental development such as deciduous tooth root resorption, permanent tooth calcification, and tooth eruption can be used to estimate age for forensic purposes.The development of the teeth are influenced by genetic, ethnicity, and sex, therefore an age estimation method must be constructed based on the same population.There were minimal significant differences in tooth development between male and female, and between right and left teeth, but there was significant difference between maxillary and mandibular teeth.The Atlas of Dental Development in the Indonesian Population constructed in this study allowed more accurate age estimation of the Indonesian sample than the other methods tested. Supplemental data for this article are available online at https://doi.org/10.1080/20961790.2021.1886648.

Application of Aspartic Acid Racemization for Age Estimation in a Spanish Sample.

Correct age-at-death estimation in adult individuals is one of the challenges of forensic investigation. Forensic anthropology macroscopic techniques are non-invasive methods for this purpose. However, several methods need to be applied to accurately estimate age, and the difference between chronological and predictive age may still be around ±10 years. New research trends are focused on the inherent process of aging, which produces changes in tissues and organs at different biochemical levels. One of the oldest and most studied approaches in this field is aspartic acid racemization. The accuracy of this technique in age estimation has been widely demonstrated. However, only a few studies have assessed its accuracy in different populations. The aim of this research was to assess the accuracy of aspartic acid racemization in a Spanish sample and its applicability to forensic cases. Dentin from fifteen third molars from two Spanish populations (ages 19-70 years old) was isolated and D and L forms of aspartic acid were detected through GC/MS, according to a previous published protocol. D/L ratios were calculated and after the application of a regression analysis, a formula for age estimation was developed. The results were similar to previous studies, obtaining an R = 0.91 between racemization ratios and age and a mean absolute error (MAE) between chronological and predictive age of 5 years. These results were ratified by leave-one-out cross-validation, as well as the application of the formula to five teeth of a known age. Despite these promising results, this technique is not exempt from drawbacks; thus, further studies are required to apply this methodology to forensic cases and to combine it with forensic anthropology findings.

Lag time of modern bomb-pulse radiocarbon in human bone tissues: New data from Brazil.

Radiocarbon analysis with reference to the modern bomb-curve was conducted using 68 bone samples of a vertebral body, femoral diaphysis, occipital bone, and parietal bone of 17 adults from Brazil. All individuals were born in 1963, thus analysis focused on the correlation with atmospheric values during the more recent, falling portion of the curve. Ages at death ranged from 43 to 54 years with representation of both sexes. Lag time (difference between the actual death date and the year of correspondence of the radiocarbon value with the curve) was evaluated for each individual and each tissue. The mean of the lag time values was 20.2 years, and the median was 22.0 years. The femur had the highest lag time median (29.5 years) among the bone groups, followed by the occipital (25.5 years), parietal (23.5 years) and the vertebra (8.0 years). The same pattern was observed for both sexes, but females tended to have lower lag time values than males. Different tissues presented considerable variation in lag time with vertebral bodies the least and the femoral diaphysis the greatest. These data suggest that individual age at death and the associated lag time must be considered in estimating the approximate death date. The lag time values for vertebral bodies were lower and with less variability in comparison with values for the occipital, parietal, and femur indicating greater consistency of that bone group for time since death estimation in the studied sample.

Root Dentin Translucency and Forensic International Dental Database: Methodology for estimation age-at-death in adults using single-rooted teeth.

Estimation of the age-at-death in adults is essential when the identification of deceased persons with unknown identity is required in both humanitarian and judicial contexts. However, the methodologies and the results obtained can be questioned. Various efforts have been developed to adjust procedures to specific populations, always seeking the precision and accuracy of the methodologies. It is known that the estimation of the age-at-death in adults coexists with wide margins of error, due to several reasons, including but not limited to statistical problems, the size of the sample or the physiological process of aging. This research focuses on a degenerative indicator of the dentin (Root Dentin Translucency) and its combination with Periodontal Height (PH) following the Lamendin's technique for estimation of the age-at-death in adults. The main objective of this research was to demonstrate the applicability of a Bayesian model based on a Forensic International Dental Database (FIDB) that include Root Translucency Height (RTH) and PH as a method to age-at-death in adults. The conclusion of this research was that the combined both indicators become a generalizable age-at-death in adults model for all human populations, where the Bayesian method would offer optimal results in any population. In this way, those populations that do not have had the possibility of validating a specific procedure, now have the opportunity to apply a valid method for estimating age-at-death in adults to global scope.

Evaluation of ancestry from human skeletal remains: a concise review.

Ancestry assessment represents a major component of forensic anthropological analysis of recovered human remains. Interpretations of ancestry, together with other aspects of the biological profile, can help narrow the search of missing persons and contribute to eventual positive identification. Such information can prove useful to authorities involved in the identification and investigative process since many lists of missing persons have a reference to this parameter. Recent research has strengthened available methodologies involving metric, non-metric morphological as well as chemical and genetic approaches. This review addresses the new anthropological techniques that are now available, as well as the complex historical context related to ancestry evaluation.

Anthropological analysis of trauma in throat bone and cartilage: A review.

In their analysis of recovered human remains, forensic anthropologists encounter structures of the throat (hyoid bone, thyroid cartilage/bone, cricoid cartilage/bone) that may present evidence of trauma. The recent published literature provides guidelines for the detection and interpretation of fractures in these tissues. Such traumatic injury frequently is associated with victims of hanging and strangulation, but many other causes have been recognized. Although the hyoid is not always recovered in skeletonized remains, it can reveal evidence of perimortem trauma and must be interpreted appropriately.

The impact of scavenging: perspective from casework in forensic anthropology.

Forensic anthropology casework frequently encounters evidence of animal scavenging associated with fragmentation and loss of skeletal material. Published research demonstrates that patterns of destruction in bone can suggest the size and type of animal involved. This study analyzes 107 cases reported on by the first author at the Smithsonian Institution to investigate patterns of scavenging in forensic anthropology casework. This investigation reveals that the extent of scavenger impact varies across the body, but primarily is concentrated in the central body area. Although extensive animal scavenging can limit analysis, some evidence of foul play can be preserved.

Recent research in Forensic Anthropology

Examination of recently published articles in four leading journals featuring forensic anthropology reveals strong research interest in the estimation of age at death and sex, trauma analysis and vari-ous other techniques of analysis. The 782 articles examined document the dynamic and evolving nature of forensic anthropology and strong re-search interest in all of the major components of the field

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Photogrammetry vs CT Scan: Evaluation of Accuracy of a Low-Cost Three-Dimensional Acquisition Method for Forensic Facial Approximation.

Photogrammetry is a three-dimensional acquisition method potentially applicable to the forensic field. This possibility requires the verification of its accuracy. In this study, 3D volumes of skulls are generated to compare the photogrammetry versus the CT scan. In order to provide eligible material to the photogrammetric software, photographs were captured at a distance of 30 cm from the skull placed on a support 1 m in height and illuminated with diffused laboratory ceiling artificial light. A Nikon Coolpix P7100 camera was used. Photographs capture common elements with the previous and the next photograph so as to allow the photogrammetric software to recognize these common points between photographs and create a 3D puzzle. The Zephyr Lite (3DFlow©) software was employed to register the 3D volume. CT-based skulls are taken as a metric reference. The photogrammetry-based skulls are then enlarged according to the measurements of some landmarks or Zygion and Zygion, the distance between end of nasal and base of nasal pyramid for frontal projection, and minimum breadth of the mandibular ramus for the right lateral projection. The accuracy of the photogrammetry is compared to that of the CT scan by measuring the 3D volumes of the skulls studied. Specific landmarks are used as reference points for the measures in both frontal and lateral views. Bland-Altman graph shows homogeneity. The mean difference (1.28 mm) indicates that the measurements taken on the photogrammetry-based skull tend to slightly overestimate compared with the measurements taken on the CT-based skull.

Fragment analysis in forensic anthropology.

Anthropological analysis of fragmentary evidence can be challenging but diverse methods allow substantial information to be gleaned. Scanning electron microscopy/energy dispersive X-ray spectroscopy enables determination if bone and/or tooth tissue is present. Protein radioimmunoassay or DNA analysis can establish the species present. Histological analysis can assist in species determination and reveal information about thermal changes. Radiocarbon analysis with special reference to the modern bomb-curve can clarify the postmortem interval. Anthropologists should also be aware that DNA analysis not only can enable positive identification but assist in the evaluation of sex and age at death.

Complex Nature of Hominin Dispersals: Ecogeographical and Climatic Evidence for Pre-Contact Craniofacial Variation.

Coordinate data analysis of ancient crania from the New World reveals complexity in interpretation when addressing ancient population dispersals. The results of this study generally support a geographic patterning for the New World; however, it also revealed a much more complex and multifactorial mechanism shaping craniofacial morphology that should be considered when investigating ecogeographic models for hominin dispersals. We show that craniofacial variation is not the result of a single mechanism but is a much more complex interaction of environmental and microevolutionary forces.

"The big sleep: Elucidating the sequence of events in the first hours of death to determine the postmortem interval".

Recent developments on postmortem interval estimation (PMI) take an advantage of the autolysis process, pointing out to the analysis of the expression of apoptosis and autophagy genes towards this purpose. Oxidative stress plays a role in this signaling as a regulatory mechanism and/or as a consequence of cell death. Additionally, melatonin has been implicated on apoptosis and autophagy signaling, making melatonin a suitable target for PMI determination. The aim of this study was to investigate the early PMI through the analysis of the expression of autophagy genes as well as oxidative stress and melatonin receptor. Our results demonstrated a rapidly increased on the expression of autophagy genes according to the expected sequence of events, then a marked decrease in this expression, matched with the switch to the apoptosis signaling. These results revealed potential candidates to analyze the PMI in the first hours of death, helping to estimate the time-since-death.

Estimation of age in forensic anthropology: historical perspective and recent methodological advances.

Estimation of age represents a central focus of forensic anthropological analysis of human skeletal remains and of the living. Advances registered in recent research include the topics of taphonomic impact, new anatomical areas of interest, histology, population variation, the dental pulp chamber, technology, mathematical approaches, biochemical analysis and techniques specifically targeting the living. This article reviews the historical development of age estimation methods and considers likely future directions.