Estimation of sex assigned at birth using dental crown and cervical measurements in a modern global sample.

Despite developing prior to the appearance of secondary sexual characteristics of the skeleton, the permanent dentition exhibits sexual dimorphism. Therefore, teeth can serve as a means to estimate sex assigned at birth even in young individuals. This project takes a large global sample of maximum dimensions of the crown as well as measurements of the crown at the cervix to explore sexual dimorphism. Dimorphism is noted in teeth throughout the dental arcade, particularly in the canines. We provide sectioning points as well as the probability of correct classification (ranging from 50.9% to 81.3%) for each measurement to aid the practitioner in sex estimation from the dentition. This research provides a method to estimate sex without arbitrary population specifications. We argue for a global approach that incorporates more population variation to remove the need to estimate "ancestry," (which in actuality is translated to a social race category) and therefore does not force sexual dimorphism-related variation into these mutable and ambiguous categories. Further, this paper demonstrates the utility of the dentition as an additional indicator to aid with the estimation of sex assigned at birth in forensic anthropology. The goal of this research is to better understand the expression of sexual dimorphism across the skeleton in a global context.

Evaluating expertise in forensic anthropology.

The medicolegal system relies on the ability of experts and non-experts alike to make judgments about expertise and use those judgments to reach consequential decisions. Given the lack of standard criteria, mandatory certification, or licensure for establishing expertise required to practice forensic anthropology and testify as an expert witness, we sought to understand how individuals assess and identify expertise in forensic anthropology by using a social science tool called the Imitation Game. This tool assesses immersion in a specific area of study via discourse, with the premise that some individuals lacking expertise themselves imitate or attempt to pass as experts. For this project we recruited volunteers with varying expertise in forensic anthropology to participate in interviews which asked questions about the practice and structure of the discipline. Those interviews were transcribed, anonymized, and evaluated by other recruited individuals with varying expertise in forensic anthropology. Results found that judges who were experts in forensic anthropology performed better than non-expert judges in determining who was not an expert in forensic anthropology based on their anonymized responses; however, nearly half of the non-experts were still able to pass as experts in forensic anthropology. The difficulties in assessing expertise based on discourse interactions demonstrates the value and need for well-defined credentials and mandatory certification to practice forensic anthropology. This study demonstrates that accurately identifying expertise in forensic anthropology may be challenging for both experts and non-experts, especially when relying solely on interactional expertise rather than formal assessments of competency which directly elucidate contributory expertise.

Mobility and kinship in the world's first village societies.

Around 10,000 y ago in southwest Asia, the cessation of a mobile lifestyle and the emergence of the first village communities during the Neolithic marked a fundamental change in human history. The first communities were small (tens to hundreds of individuals) but remained semisedentary. So-called megasites appeared soon after, occupied by thousands of more sedentary inhabitants. Accompanying this shift, the material culture and ancient ecological data indicate profound changes in economic and social behavior. A shift from residential to logistical mobility and increasing population size are clear and can be explained by either changes in fertility and/or aggregation of local groups. However, as sedentism increased, small early communities likely risked inbreeding without maintaining or establishing exogamous relationships typical of hunter-gatherers. Megasites, where large populations would have made endogamy sustainable, could have avoided this risk. To examine the role of kinship practices in the rise of megasites, we measured strontium and oxygen isotopes in tooth enamel from 99 individuals buried at Pinarbasi, Boncuklu, and Çatalhöyük (Turkey) over 7,000 y. These sites are geographically proximate and, critically, span both early sedentary behaviors (Pinarbasi and Boncuklu) and the rise of a local megasite (Çatalhöyük). Our data are consistent with the presence of only local individuals at Pinarbasi and Boncuklu, whereas at Çatalhöyük, several nonlocals are present. The Çatalhöyük data stand in contrast to other megasites where bioarchaeological evidence has pointed to strict endogamy. These different kinship behaviors suggest that megasites may have arisen by employing unique, community-specific kinship practices.

An Anthropological Investigation of the Sociocultural and Economic Forces Shaping Dental Crowding Prevalence.

OBJECTIVE: The aim of the current study is to explore country of origin and social race category differences in dental crowding prevalence through an anthropological approach. DESIGN: Data were collected from individuals within five countries (Australia, China, Japan, South Africa, United States; n = 1008) and seven social race groups in two countries (American Black, American White, Latinx, and Indigenous in the United States, South African Black, South African White, and South African Coloured; n = 654). Statistical significance between groups was assessed with a Kruskal-Wallis test, while a Dunn's post-hoc test identified which groups significantly differed. RESULTS: Results indicate South Africa is characterized by the lowest frequencies of dental crowding, with Coloured South Africans yielding the highest and Black South Africans displaying the lowest frequencies. Individuals in the United States exhibited relatively high levels of minor dental crowding. American Blacks had lower crowding levels, while the Indigenous group had high levels of severe crowding. Individuals within China and Japan exhibited higher relative prevalence of severe crowding. CONCLUSIONS: Overall, significant differences exist in dental crowding prevalence across countries and social race categories using an anthropological grading system to assess crowding. These differences are likely impacted by sociocultural (aesthetic preferences) and economic (access to dental care) factors.

Agreement and error rates associated with standardized data collection protocols for skeletal and dental data on 3D virtual subadult crania.

Observer error and agreement rates for craniometrics, odontometrics, and cranial and dental morphological traits have been inconsistently evaluated on three-dimensional cranial reconstructions and almost never assessed on subadult individuals. This study uses a computed tomography (CT) scan sample of 12 subadults aged between birth and 20 years from the Subadult Virtual Anthropology Database (SVAD) to evaluate intra- and inter-observer error and agreement rates associated to these four types of data on virtual crania. Forty-eight cranial landmarks, 33 standard inter-landmark distances (ILDs), 13 cranial macromorphoscopic traits, four permanent and four deciduous dental landmarks and measurements per tooth, and 21 permanent and 12 deciduous dental morphological traits were collected on each individual. Results matched or improved on published standards for dry bones, teeth, or dental casts. Technical Error of Measurement (TEM) associated with metric data ranged from 0.00 mm to 0.99 mm and relative TEM ranged from 0% to 5.76%. Cohen's kappa coefficient values for agreement on morphological traits scores were above K = 0.5 for 90% of the traits. Type III cranial landmarks showed higher error rates than Type I and II cranial landmarks. Agreement on dental morphology scores seemed influenced by observer experience and rater agreement improved when using di- or tri-chotomized grades. Skeletal maturity did not significantly affect error rates, meaning most craniofacial and dental metrics and morphological traits can be reliably obtained from virtual subadult crania.

Responding to the American Academy of Forensic Sciences vision, mission, and values statements: Comments, revisions, and proposed actions.

•We call for revisions to the current AAFS vision, mission, and values statements.•Truly aspirational statements will provide guiding principles for forensic scientists.•Revisions should meaningfully engage with issues of diversity and equity.•Our goal of pursuing justice should also extend to our practitioner community.•We envision AAFS committees of diverse membership making positive changes to the statements.

Forensic Anthropology as a Discipline.

This paper explores the current state of forensic anthropology in the United States as a distinct discipline. Forensic anthropology has become increasingly specialized and the need for strengthened professionalization is becoming paramount. This includes a need for clearly defined qualifications, training, standards of practice, certification processes, and ethical guidelines. Within this discussion, the concept of expertise is explored in relation to professionalization and practice, as both bioarchaeology and forensic anthropology have different areas of specialist knowledge, and therefore unique expertise. As working outside one's area of expertise is an ethical violation, it is important for professional organizations to outline requisite qualifications, develop standards and best practice guidelines, and enforce robust preventive ethical codes in order to serve both their professional members and relevant stakeholders.

Historic and bioarchaeological evidence supports late onset of post-Columbian epidemics in Native California.

Catastrophic decline of Indigenous populations in the Americas following European contact is one of the most severe demographic events in the history of humanity, but uncertainty persists about the timing and scale of the collapse, which has implications for not only Indigenous history but also the understanding of historical ecology. A long-standing hypothesis that a continent-wide pandemic broke out immediately upon the arrival of Spanish seafarers has been challenged in recent years by a model of regional epidemics erupting asynchronously, causing different rates of population decline in different areas. Some researchers have suggested that, in California, significant depopulation occurred during the first two centuries of the post-Columbus era, which led to a "rebound" in native flora and fauna by the time of sustained European contact after 1769. Here, we combine a comprehensive prehistoric osteological dataset (n = 10,256 individuals) with historic mission mortuary records (n = 23,459 individuals) that together span from 3050 cal BC to AD 1870 to systematically evaluate changes in mortality over time by constructing life tables and conducting survival analysis of age-at-death records. Results show that a dramatic shift in the shape of mortality risk consistent with a plague-like population structure began only after sustained contact with European invaders, when permanent Spanish settlements and missions were established ca. AD 1770. These declines reflect the syndemic effects of newly introduced diseases and the severe cultural disruption of Indigenous lifeways by the Spanish colonial system.

Perceptions of Race and Ancestry in Teaching, Research, and Public Engagement in Biological Anthropology.

The concept of race has a complex history in the field of biological anthropology. Despite increased recognition of the racist origins of the discipline, there remains little agreement about what the concept means, how it is used, or how it is discussed. This study presents the results of a survey of biological anthropologists to investigate the relationship of biological anthropologists with race and ancestry. The survey focuses on the areas of research, public engagement, and teaching as related to these concepts. Results indicate that a large majority of biological anthropologists agree that race (as a social not biological concept) is separate from ancestry. The majority of respondents agreed that ancestry categories should be based on geography (e.g., Asian, European, and African), and more anthropologists thought the terms "Hispanic" and "Latino" were inappropriate ancestry categories. While most respondents felt that discussions of these terms were not matters of "political correctness," nearly a quarter of respondents suggested that concerns over the moral and ethical implications of research (e.g., photos, terminology, and ancestry) result in the silencing of anthropological research. Overwhelmingly, respondents felt that anthropologists have a responsibility to ensure the avoidance of misappropriation of their work by race science and by white nationalists/supremacists. Some differences in survey responses were found relating to respondents' subdiscipline, educational level, location, age, self-identified racial/ethnic categories, and gender. In regard to teaching, survey results indicate that these concepts are minimally covered in university classrooms. When taught, topics focus on the colonialist/racist history of anthropology, the presence of white privilege/supremacy, and racism. Based on the results of this survey, the authors argue for greater public engagement on these concepts, a standardized system of teaching race and ancestry, and a disciplinary conversation about practice and terminology. In this way, biological anthropologists can best place themselves to combat racism in a socially responsible way.

A comparison of subadult skeletal and dental development based on living and deceased samples.

OBJECTIVES: A fundamental assumption in biological anthropology is that living individuals will present with different growth than non-survivors of the same population. The aim is to address the question of whether growth and development data of non-survivors are reflective of the biological consequences of selective mortality and/or stress. MATERIALS AND METHODS: The study compares dental development and skeletal growth collected from radiographic images of contemporary samples of living and deceased individuals from the United States (birth to 20 years) and South Africa (birth to 12 years). Further evaluation of deceased individuals is used to explore differential patterns among manners of death (MOD). RESULTS: Results do not show any significant differences in skeletal growth or dental development between living and deceased individuals. However, in the South African deceased sample the youngest individuals exhibited substantially smaller diaphyseal lengths than the living sample, but by 2 years of age the differences were negligible. In the US sample, neither significant nor substantial differences were found in dental development or diaphyseal length according to MOD and age (>2 years of age), though some long bones in individuals <2 years of age did show significant differences. No significant differences were noted in diaphyseal length according to MOD and age in the SA sample. DISCUSSION: The current findings refute the idea that contemporary deceased and living individuals would present with differential growth and development patterns through all of ontogeny as well as the assumptions linking short stature, poor environments, and MOD.

Scientific integrity in the forensic sciences: Consumerism, conflicts of interest, and transparency.

The goal of this paper is to discuss scientific integrity, consumerism, conflicts of interest, and transparency within the context of forensic science. Forensic scientists play crucial roles within the legal system and are constantly under various pressures when performing analytical work, generating reports based on their analyses, or testifying to the content of these reports. Maintaining the scientific integrity of these actions is paramount to supporting a functional legal system and the practice of good science. Our goal is to discuss the importance of scientific integrity as well as the factors it may compromise, so that forensic practitioners may be better equipped to recognize and avoid conflicts of interest when they arise. In this discussion we define terms, concepts, and professional relationships as well as present three case studies to contextualize these ideas.

Patterns in Forensic Decapitations: A Review of the Literature and Case Report.

Separation of the head from the body can occur for a variety of reasons and in various locations across the neck. This study presents a review of the literature to identify the patterns of decapitations in forensic cases in relation to manner of death, age, and anatomical location (n = 88). The most common manner of death was suicide, followed by homicide and then accident. Ages ranged from 32 weeks prenatal to 85 years. Decapitation is reported at higher rates for individuals between 19 and 65. The majority of decapitations occurred at the midneck (second to fifth cervical vertebrae), followed by the upper neck and then the lower neck. This pattern holds true for all manners of death; however, in homicides, the percentage occurring at the midneck decreases. The findings of this study indicate some patterns in terms of manner of death, age, and location of decapitation, which could aid the medicolegal community in interpreting neck trauma. A case study is also briefly presented to illustrate findings.

Bioarchaeology of Neolithic Çatalhöyük reveals fundamental transitions in health, mobility, and lifestyle in early farmers.

The transition from a human diet based exclusively on wild plants and animals to one involving dependence on domesticated plants and animals beginning 10,000 to 11,000 y ago in Southwest Asia set into motion a series of profound health, lifestyle, social, and economic changes affecting human populations throughout most of the world. However, the social, cultural, behavioral, and other factors surrounding health and lifestyle associated with the foraging-to-farming transition are vague, owing to an incomplete or poorly understood contextual archaeological record of living conditions. Bioarchaeological investigation of the extraordinary record of human remains and their context from Neolithic Çatalhöyük (7100-5950 cal BCE), a massive archaeological site in south-central Anatolia (Turkey), provides important perspectives on population dynamics, health outcomes, behavioral adaptations, interpersonal conflict, and a record of community resilience over the life of this single early farming settlement having the attributes of a protocity. Study of Çatalhöyük human biology reveals increasing costs to members of the settlement, including elevated exposure to disease and labor demands in response to community dependence on and production of domesticated plant carbohydrates, growing population size and density fueled by elevated fertility, and increasing stresses due to heightened workload and greater mobility required for caprine herding and other resource acquisition activities over the nearly 12 centuries of settlement occupation. These changes in life conditions foreshadow developments that would take place worldwide over the millennia following the abandonment of Neolithic Çatalhöyük, including health challenges, adaptive patterns, physical activity, and emerging social behaviors involving interpersonal violence.

A Test of Age Estimation Methods on Impacted Third Molars in Males.

This study tests the relationship between third molar impaction and its concomitant effect on age estimation methods. Data were collected on radiographs of males analyzed in the Defense POW/MIA Accounting Agency Laboratory (n = 114). Radiographs of skeletonized individuals were scored for dental development, and age was assigned based on the appropriate ancestry-based method. Differences between identified age and estimated dental age were assessed to determine whether molar impaction affected root development and age estimations. Results indicate that impacted teeth tend to be underdeveloped and result in age estimates that are too low. While these results are of note to anthropologists and odontologists performing dental age estimates, more work is needed to explore the effect of impaction on development among a more diverse sample.

Observer error and its impact on ancestry estimation using dental morphology.

Dental morphology is becoming increasingly visible in forensic anthropology as part of the estimation of ancestry. As methods are developed based on these data, it is important to understand the role of observer error in data collection and method application. In this study, 10 observers collected dental morphological data on 19 traits on the same set of nine plaques. Various measures of interrater reliability were calculated to assess observer error. Data were then input into one of three ancestry estimation methods based on dental morphology to understand the role of observer error in these methods. Results show low rater reliability for all dental morphological traits when all 10 observers are compared. Rater reliability increases when only experienced observers are compared and traits are dichotomized. Further, differences in trait scores by observers resulted in disparate estimations of ancestry in each of the methods. While observer error appears to be an issue in dental morphological methods of ancestry estimation, these problems can be addressed. An argument is made for advanced training in dental anthropology in laboratories and in graduate programs. Further, methods need to test for and employ traits with high rater agreement.

Environmental selection during the last ice age on the mother-to-infant transmission of vitamin D and fatty acids through breast milk.

Because of the ubiquitous adaptability of our material culture, some human populations have occupied extreme environments that intensified selection on existing genomic variation. By 32,000 years ago, people were living in Arctic Beringia, and during the Last Glacial Maximum (LGM; 28,000-18,000 y ago), they likely persisted in the Beringian refugium. Such high latitudes provide only very low levels of UV radiation, and can thereby lead to dangerously low levels of biosynthesized vitamin D. The physiological effects of vitamin D deficiency range from reduced dietary absorption of calcium to a compromised immune system and modified adipose tissue function. The ectodysplasin A receptor (EDAR) gene has a range of pleiotropic effects, including sweat gland density, incisor shoveling, and mammary gland ductal branching. The frequency of the human-specific EDAR V370A allele appears to be uniquely elevated in North and East Asian and New World populations due to a bout of positive selection likely to have occurred circa 20,000 y ago. The dental pleiotropic effects of this allele suggest an even higher occurrence among indigenous people in the Western Hemisphere before European colonization. We hypothesize that selection on EDAR V370A occurred in the Beringian refugium because it increases mammary ductal branching, and thereby may amplify the transfer of critical nutrients in vitamin D-deficient conditions to infants via mothers' milk. This hypothesized selective context for EDAR V370A was likely intertwined with selection on the fatty acid desaturase (FADS) gene cluster because it is known to modulate lipid profiles transmitted to milk from a vitamin D-rich diet high in omega-3 fatty acids.

Northern exposure: Mandibular torus in the Greenlandic Norse and the whole wide world.

OBJECTIVES: In the first issue of the American Journal of Physical Anthropology, E.A. Hooton noted the expression of Eskimoid characteristics in the Icelandic skull, one of which was mandibular torus. Our goal is to evaluate this trait in another North Atlantic population, the Greenlandic Norse. MATERIALS AND METHODS: An investigation of mandibular torus was carried out on all Greenlandic Norse skeletons disinterred up to 1986 (n = 109), along with comparative samples from Iceland (n = 82), Norway (n = 98), and Denmark (n = 64). Torus expression was scored on a six grade scale with absence and five degrees of trait presence. RESULTS: Greenlanders and Icelanders show extraordinarily high frequencies (65-97%) and pronounced expressions of mandibular torus. More surprising was the almost complete absence of this trait in a Danish Viking sample (9%) and a significantly lower frequency in medieval Norwegians (48%). DISCUSSION: The dramatic expression of mandibular torus in the Greenlandic Norse and their contrast to related Scandinavian populations in Europe stimulated the collection of data from the literature and the database of Christy G. Turner II for 49,970 individuals in 335 populations. When plotted on a global scale, mandibular torus shows a strong clinal distribution with the highest frequencies in northern latitudes and the lowest frequencies around the equator. Although mandibular torus has some hereditary component, as indicated by family studies, the trait has a strong environmental component of variance. How factors of a northern environment, including climatic stress and dietary behavior, influence torus expression remains enigmatic.

The taphonomy of human remains in a glacial environment.

A glacial environment is a unique setting that can alter human remains in characteristic ways. This study describes glacial dynamics and how glaciers can be understood as taphonomic agents. Using a case study of human remains recovered from Colony Glacier, Alaska, a glacial taphonomic signature is outlined that includes: (1) movement of remains, (2) dispersal of remains, (3) altered bone margins, (4) splitting of skeletal elements, and (5) extensive soft tissue preservation and adipocere formation. As global glacier area is declining in the current climate, there is the potential for more materials of archaeological and medicolegal significance to be exposed. It is therefore important for the forensic anthropologist to have an idea of the taphonomy in this setting and to be able to differentiate glacial effects from other taphonomic agents.

Morphoscopic Trait Expression in "Hispanic" Populations.

This study evaluates population variation of eight cranial morphoscopic traits using samples of known southwest Hispanics (n=72), Guatemalans (n=106), American Blacks (n=146), and American Whites (n=218). We applied the support vector machine (SVM) method to build a prediction model based on a subsample (20%) of the data; the remainder of the data was used as a test sample. The SVM approach effectively differentiated between the four groups with correct classification rates between 72% (Guatemalan group) and 94% (American Black group). However, when the Guatemalan and southwest Hispanic samples were pooled, the same model correctly classified all groups with a higher degree of accuracy (American Black=96%; American White=77%; and the pooled Hispanic sample=91%). This study also identified significant differences between the two Hispanic groups in six of the eight traits using univariate statistical tests. These results speak to the unique population histories of these samples and the current use of the term "Hispanic" within forensic anthropology. Finally, we argue that the SVM can be used as a classification model for ancestry estimation in a forensic context and as a diagnostic tool may broaden the application of morphoscopic trait data for the assessment of ancestry.

The use of tooth crown measurements in the assessment of ancestry.

As the hardest tissue in the body, teeth have the potential to offer a wealth of biological information to the forensic anthropologist, which can include the assessment of ancestry. Using a large data set of dental measurements, the efficacy of mesiodistal and buccolingual tooth dimensions to discriminate between broad, geographically based groups is explored. A general pattern is identified: African populations have the largest teeth, Asians possess teeth of intermediate size, and Europeans have the smallest teeth. In a discriminant function analysis using crown measurements of all teeth (mandibular and maxillary and excluding the third molar), individuals were correctly classified in 71.3% of cases. When the sex of the individual is known, classification is improved up to 88.1% in females and 71.9% of males (cross-validated). Based on these results, we argue that dental metrics can be regularly employed as part of the development of the biological profile.