Craniometric variation and ancestry estimation in two contemporary Caribbean populations

Forensic evaluation of craniometric characteristics of the Kazakhstan population

Background

The human skull is the part of the skeleton most frequently used in population studies, as it was more exposed to genetic factors and less exposed to environmental factors. The skull is an important component in human forensic identification.

Materials and methods

The craniometric characteristics of 186 male and 114 female skulls found on the territory of Kazakhstan were studied. Dimensions were measured using standard anthropometric methods and instruments. The results of measurements of 25 craniometric parameters are presented. Methods of descriptive and parametric statistics were used.

Results

Statistical analysis showed significant regional dimorphism, confirming theindividuality of the Kazakhstan population. Statistically significant deviations werefound in 6 male craniometric characteristics and 4 female craniometric characteristics(p<0.05). The most dimorphous variables for regional identification in Kazakhstanmales were the higher skull base and frontal chord width , full face height , condylarand bigonial width , and low mandibular body reference values (p<0.05). For females,significant statistical discrepancies were seen in the transverse diameter and skullbase width, mastoid and occipital aperture width (p<0.05).

Conclusion

The recorded variations and changes in the morphology of the humanskull of the population of Kazakhstan indicate the need to develop and updateosteometric standards used in practice for specific populations. All this will significantlyimprove the accuracy of forensic identification and more fully study the biologicalpatterns of population formation, as well as evaluate the comparative effectiveness ofindividual features in the reconstruction of the population history of various populationgroups.

Exploratory analysis of new craniometric measures for the investigation of biological sex using open-access statistical and machine-learning tools on a cone-beam computed tomography sample

Investigation of the biological sex of human remains is a crucial aspect of physical anthropology. However, due to varying states of skeletal preservation, multiple approaches and structures of interest need to be explored. This research aims to investigate the potential use of distances between bifrontal breadth (FMB), infraorbital foramina distance (IOD), nasal breadth (NLB), inter-canine width (ICD), and distance between mental foramina (MFD) for combined sex prediction through traditional statistical methods and through open-access machine-learning tools. Ethical approval was obtained from the ethics committee, and out of 100 cone beam computed tomography (CBCT) scans, 54 individuals were selected with all the points visible. Ten extra exams were chosen to test the predictors developed from the learning sample. Descriptive analysis of measurements, standard deviation, and standard error were obtained. T-student and Mann-Whitney tests were utilized to assess the sex differences within the variables. A logistic regression equation was developed and tested for the investigation of the biological sex as well as decision trees, random forest, and artificial neural networks machine-learning models. The results indicate a strong correlation between the measurements and the sex of individuals. When combined, the measurements were able to predict sex using a regression formula or machine learning based models which can be exported and added to software or webpages. Considering the methods, the estimations showed an accuracy rate superior to 80% for males and 82% for females. All skulls in the test sample were accurately predicted by both statistical and machine-learning models. This exploratory study successfully established a correlation between facial measurements and the sex of individuals, validating the prediction potential of machine learning, augmenting the investigative tools available to experts with a high differentiation potential.

Caribbeanist casualties: Interrogating the application of structural vulnerability to forensic anthropology

Biocultural approaches are instrumental to the evolution of forensic anthropology, and this practice must first reckon with its own violences before it can ethically address structural violence at large. We take up the issue of coerced migrations of Caribbean populations and forensic practice at the southern border of the United States, to problematize how forensic identification standards contribute to the casualties of ethnic erasures and potentially exacerbate structural vulnerability of Black Caribbean populations. We put forward that forensic anthropology is complicit in maintaining inequality in death and identification for Black Caribbean migrants through the absence of necessary reference data and methods of population-affinity estimation, and the adoption of fundamentally flawed linguistic constructions of Blackness. Pushing forensic anthropology to continue engaging with the colonial logics that have shaped its understanding and motivation for quantifying human biologies is key in efforts toward a progressive disciplinary future.

[Craniometric aspects in forensic medical identification of the Kazakhstan population]

The aim of this study is to estimate the variability limits of craniometric skull parameters, revealed in Kazakhstan, and find out significant criteria for forensic medical identification of the local population. The investigation included 25 standard craniometric skull parameters, revealed in Kazakhstan. Standard antropometric tests and tools were used. Current study confirm that the craniometrics indicators of Kazakhstan population have specific regional features. The skulls, revealed in Kazakhstan, are well craniometrically differentiated. Statistically significant differences were found out in 6 craniometric parameters in men (width of skull base, frontal chord, full face height, condylar and bigonial width, mandibular height) and in 4 parameters in women (transverse diameter, width of skull base, mastoid width, width of occipital foramen). The usage of updated data according to the regional features of the craniometrics parameters allow to significantly improve the forensic identification accuracy, study more completely the biological regularities of population formation and assess the comparative efficacy of individual features in the population reconstructions.

Assessment of the Possibilities of Forensic Identification Population of Kazakhstan by Craniometric Indicators

BACKGROUND: Craniometric indicators are one of the most reliable sources of information about the population. Despite the development of genetic methods, skull measurements are extremely important in anthropology and forensic medicine. In addition to the history of population development, environmental factors such as climate and lifestyle contribute to variations in human skull shape. Due to the high variability of human individuals, the anthropological study of the population is carried out selectively, with a comparison of different population groups (ethnic, professional, age, gender). The lack of clear ideas about the typical parameters and proportions of the skull among the people of Kazakhstan creates a certain gap in forensic-medical identification. AIM: The aim of the work is to check the hypothesis about the relationship between variations in skull morphology and changes in craniometric indicators with climatic conditions and the specifics of lifestyle in populations living in different territories of Kazakhstan. METHODS: 187 male and 114 female adult skulls found on the territory of the two largest regions of Kazakhstan were examined. The variable variability of 25 craniometric indicators of skulls found on the territory of Central and South Kazakhstan was studied. All osteometric changes were performed using standard anthropometric instruments, followed by the calculation of craniometric indices. Multidimensional statistics were applied. RESULTS: The two populations demonstrate differences in craniometric indicators formed in different geographical and ecological conditions, regardless of gender. It was found that the sizes of the skulls found in the two studied regions of Kazakhstan statistically significantly differ in 5 craniometric indicators for men and 8 craniometric indicators for women. Significant changes were noted in the size of the full and upper height of the face, the average width of the face, the height of the body of the lower jaw and the height of the nose in men.  The most dimorphic variables for forensic medical evaluation in the studied populations of female skulls were transverse, altitudinal and zygomatic diameters, mastoid width, width of the base of the skull, width of the occipital foramen, upper face height and nose height. The shape of the skulls found in the studied territories is predominantly brachycephalic. The cranial index was >81.1% - at men, 83% - at women. The study showed that race affects the size of the skull, regardless of gender. Craniometric parameters in male and female skulls vary according to different criteria. In women between races, there are statistically significant differences in the size of the width of the occipital foramen and the average width of the face. Statistically significant differences in the width of the base of the skull, the zygomatic diameter and the average width of the face between the Caucasoid and Mongoloid races were revealed in the studied regions in men. The established differences made it possible to form additional differential diagnostic criteria. CONCLUSION: Identification of the features inherent in the population living in certain territories provides auxiliary information for medical and forensic identification of a person. In this study, population-specific craniometric indicators have been developed for inhabitants of two regions of Kazakhstan, which expand and complement identification capabilities when categorizing skeletal remains found in these territories.

ANINet: a deep neural network for skull ancestry estimation

BACKGROUND

Ancestry estimation of skulls is under a wide range of applications in forensic science, anthropology, and facial reconstruction. This study aims to avoid defects in traditional skull ancestry estimation methods, such as time-consuming and labor-intensive manual calibration of feature points, and subjective results.

RESULTS

This paper uses the skull depth image as input, based on AlexNet, introduces the Wide module and SE-block to improve the network, designs and proposes ANINet, and realizes the ancestry classification. Such a unified model architecture of ANINet overcomes the subjectivity of manually calibrating feature points, of which the accuracy and efficiency are improved. We use depth projection to obtain the local depth image and the global depth image of the skull, take the skull depth image as the object, use global, local, and local + global methods respectively to experiment on the 95 cases of Han skull and 110 cases of Uyghur skull data sets, and perform cross-validation. The experimental results show that the accuracies of the three methods for skull ancestry estimation reached 98.21%, 98.04% and 99.03%, respectively. Compared with the classic networks AlexNet, Vgg-16, GoogLenet, ResNet-50, DenseNet-121, and SqueezeNet, the network proposed in this paper has the advantages of high accuracy and small parameters; compared with state-of-the-art methods, the method in this paper has a higher learning rate and better ability to estimate.

CONCLUSIONS

In summary, skull depth images have an excellent performance in estimation, and ANINet is an effective approach for skull ancestry estimation.