Biological Distance Research Articles

Geographic and temporal diversity in dental morphology reflects a history of admixture, isolation, and drift in African Americans

While genetic studies have documented variation in admixture proportions in contemporary African Americans across the US, relatively little is known about the socio-historical roots of this variation. Our goal in this study is to use dental morphology to explore the socio-historical correlates of admixture, localized gene flow, and drift in African Americans. Our data are ordinally-graded dental morphological traits scored in 196 Africans, 335 Europeans and European Americans, 291 pre-Spanish-contact Native Americans, and 722 African Americans. The African American data derived from contemporary and historic samples. We eliminated from analysis individuals and traits with greater than 20% missing data. We summarized the major axes of trait variation using principal component analysis (PCA), estimated biological distance, constructed multidimensional scaling (MDS) plots of the distances, and measured the correlation between geographic and biological distance. In the PCA, African American groups clustered between Africans and Europeans on PC 1, reflecting admixture between the groups. PC 2 separated African American samples, possibly reflecting movement, isolation, and drift. MDS analyses confirmed the existence of sizable biological distances between African American samples, especially between contemporary and past African American samples. We found no relationship between biological and geographic distances. We demonstrate that admixture and drift can be inferred from multi-variable analyses of patterns of dental morphology in admixed populations. Localized gene flow has not affected patterns of trait variation in African Americans, but long-range movement, isolation, and drift have. We connect patterns of dental trait variation to efforts to flee oppression during the Great Migration, and the repeal of anti-miscegenation laws.

Use of craniometric data to facilitate migrant identifications at the United States/Mexico border.

Thousands of migrants have died along the United States/Mexico border and many remain unidentified. The purpose of this research is to test whether estimations of population affinity, derived from craniometric data, can facilitate identification of migrant remains and provide a geographic region of origin rather than the broad label Hispanic. The appropriateness of current forensic reference data will also be assessed. A case study combined with craniometric data from positively identified and unidentified migrants from the Pima County Office of the Medical Examiner (n=489) in Arizona and operation identification (n=201) in Texas were compared to skeletal data representing Guatemalan (n=87) and Mexican (n=65) Mayans. Biological distance and discriminant function analyses were used to assess overall population relationships and classificatory models for forensic anthropological application. The majority of evidence indicates that estimations of population affinity can assist in the facilitation identification of migrant remains, even when a broad classification is used. Biological distances among the groups suggest that positively identified Guatemalan and Mexican migrants are similar to one another but differ from Guatemalan and Mexican Mayans. Population affinity estimations can aid migrant identification, and current reference data used in forensic anthropological practice should be replaced with data from positive identifications. Estimates of geographic origin may be more useful than the broad generic term Hispanic for narrowing down the search for a missing person, but more data and research is needed to achieve this goal. Although, the utility of geographic origin estimates relies on transnational data centralization and sharing, which is not always the case.

Tratamento estético: Aumento de coroa clínica inferior

Atualmente a busca por um sorriso perfeito vem aumentando e se tornando uma exigência comum na prática clínica odontológica. Este artigo tem como objetivo apresentar um relato de caso de um tratamento estético cirúrgico para um paciente com excesso de gengiva dos dentes inferiores. A cirurgia de aumento de coroa clínica demonstrou uma forma de devolver as distâncias biológicas adequadas para restabelecer saúde, função e estética do caso proposto, proporcionando resultados satisfatórios tanto para o paciente quanto para o cirurgião-dentista.

Moving Forward: A Bioarchaeology of Mobility and Migration

Growing interest in bioarchaeology and its ability to address complex questions tied to social and biological identities in the past has led to the development of nuanced methods for evaluating mobility and migration using human skeletal remains. Improving our ability to identify both short- and long-term migration through observations of body modification, analyses of biological distance, and applications of biogeochemical and aDNA techniques has enabled us to move beyond the simple dichotomous classification of past individuals as either local or nonlocal. These approaches have elucidated the complexity of migration processes while also revealing the heterogeneous ways in which individual agents and social groups incorporate, instigate, experience, and adapt to movement. These data have likewise demonstrated the potential of bioarchaeology to reveal broader patterns of social organization, social and ethnic identities, fictive kinship, postmarital residence, gender roles and relations, detailed life courses, responses to climate stress, and pathways of disease transmission. As bioarchaeology continues to contribute to mobility and migration studies, human skeletal data should be further contextualized by the archaeological record and linked to anthropological, archaeological, and bioarchaeological theoretical frameworks as part of more holistic attempts to explain the diversity and dynamics of human movement, interaction, and identity construction among communities in the past.

Frontal sinus anatomy of the noble Swéerts-Sporck family and verification of their biological relationships using similarity analysis.

The evaluation of frontal sinus similarity is one way to detect biological relationships, especially in small groups, including families of historically known personalities. However, possibilities for studying this issue are currently limited. This contribution deals with the frontal sinuses of a rare osteological sample with known genealogical data, members of the noble Swéerts-Sporck family from the 17th to 20th centuries. The aim is to verify whether the frontal sinuses reflect documented family relationships. Basic dimensions of the frontal sinus such as total surface area and volume, and maximum height and width, and also morphology and anatomical features were evaluated using computed tomography scans. The portions of the frontal sinus above the "external supraorbital line" were analyzed. The degree of similarity between biologically related individuals was determined for each variable and compared with their known biological distance. The degree of similarity based on dimensions was evaluated using both the unadjusted measured data and standardized data adjusted to size. For the unadjusted dimensions, a positive correlation between morphological similarity and biological relatedness was apparent. On the other hand, no positive correlation was apparent for most of the standardized data. Only total volume showed a very weak indication of a positive trend in the standardized data, but this was weaker than in the original values. A positive quantifiable relationship between morphological patterns and biological distance is not clearly indicated. However, nonmetric features do support the documented relationships of the individuals.

Biological relationships and frontal sinus similarity in skeletal remains with known genealogical data.

Frontal sinus analysis has potential utility for detecting biologically related individuals. However, the methodological approach to its evaluation, as well as its informative value, have been questioned. The aim of this work is to introduce a new approach to evaluating the frontal sinus using the 'external supraorbital line' (ESOL) and to determine whether there are sex differences within families in frontal sinus measurements and whether frontal sinus similarity reflects known genetic relationships in both measurements and morphology. We examined the skeletal remains of 41 adult individuals (25 males, 16 females), all members of one family over four generations (19th to 20th centuries), including individuals with very close consanguinity. CT images of skulls were acquired, and both the dimensions and morphology of the frontal sinuses were analyzed using their portions above the ESOL. No significant sex differences were found within families based on frontal sinus dimensions. Significant relationships were found between biological distance and the maximum height and morphology of the frontal sinuses. The greatest degree of similarity was found among closely related individuals. Additionally, in several cases, there was a greater degree of similarity between first cousins or grandparents and their grandchildren than among siblings or parents and their children. Total surface, volume and width are not significant indicators of relatedness. Known genetic relationships are also supported by individual morphological features. Variability within families with very close consanguineous relationships was lower than within families with common degrees of consanguinity, although differences are significant only for some variables.

Trade Relationships and Gene Flow at Pottery Mound Pueblo, New Mexico

Pottery Mound is a large Ancestral Puebloan site situated within the Middle Rio Grande (MRG) region of New Mexico. This article adds to our understanding of relationships between Pottery Mound, the Western Pueblos, and Mexico through use of biological distance analysis based on dental nonmetric traits. Extensive material and cultural influences, as well as migration events from Western Pueblos to Pottery Mound, have been proposed by several scholars, while others have highlighted parallels to Mexico, especially Paquimé. A total of 1,528 individuals from the U.S. Southwest and Mexico were used to examine relationships between Pottery Mound and these areas. We find no evidence of close biological similarity between Pottery Mound and the Western Pueblos or northern Mexico. Instead, the results indicate biological affinity between Pottery Mound and sites in the MRG region and Mogollon areas. This similarity suggests that although there is evidence for trade between Pottery Mound and other sites in the southwestern United States and Mesoamerica, trade may not have been accompanied by significant gene flow from those areas from which the trade goods originated. It is possible that neighboring regions, such as the Mogollon, served as intermediaries for trade between Pottery Mound and distant regions.

The Potential for Discrepancies in Population History Signatures from Different Segments of the Human Skeleton

The use of metric data from skeletal remains to assess models of evolutionary processes is a well‐established substitute for genomic data. However, it has been suggested in previous research that certain osteological elements retain population history signatures better than others because they are likely less subject to natural selection. This study examines the potential for differences in gene flow models using human crania (traits shown to evolve through neutral processes) versus postcrania (traits provisionally shown to have evolved in response to selection). In this study, we sampled from four large pueblos in the American Southwest representing a short temporal period and small geographic area (Arizona, c. 1200–1400, N=267). Based on a robust archaeological record detailing changes in material culture, researchers hypothesize immigration into this region from non‐local populations.The study uses gene flow models based on variance comparison methods developed by Relethford and Blangero. Metric data were analyzed using the R statistical environment and RMET 5.0, a program based on the Relethford‐Blangero statistics. Under a quantitative genetic model, gene flow results in higher‐than‐expected variance in a population, which RMET examines. Likewise, gene flow decreases the biodistance between populations sharing genes, and so these were compared through Mahalanobis D2 distances.Cranial and postcranial dimensions generally result in different patterns of gene flow. Comparing residual phenotypic variances from the Relethford‐Blangero model, only one of the four sites presents the same pattern of gene flow between cranial and postcranial results. Biodistance analyses show that the Pueblo population that is the greatest distance remains consistent in both crania and postcrania, but which of the other three is closest changes between the two body regions. This incongruence has implications for local disparities in the variance and in the mean differences between aspects of morphology.Either the upper or lower limb elements may be driving the discrepancies, as limb bones are shown to respond dissimilarly to selection on a global scale. We conducted analyses comparing results of the upper and lower limbs. The results indicate upper limb residual variances are higher, but only the lower limb matches the patterns observed in the overall postcranial analysis. Biological distance relationships are very similar between the limbs, though the lower limb data is closer in magnitude to the overall postcranial distance. It is possible that the lower limb is driving the variance results for the postcrania, a result that provisionally reflects the evolution of femoral traits in recent humans in response to neutral processes. This has implications for how we evaluate population history using phenotypic data, particularly considering which phenotypic data to employ.Support or Funding InformationThis research was partially funded by the University of Tennessee Department of Anthropology through a Kneberg‐Lewis Scholarship.

Prioritizing Gene Cascading Paths to Model Colorectal Cancer Through Engineered Organoids.

Engineered organoids by sequential introduction of key mutations could help modeling the dynamic cancer progression. However, it remains difficult to determine gene paths which were sufficient to capture cancer behaviors and to broadly explain cancer mechanisms. Here, as a case study of colorectal cancer (CRC), functional and dynamic characterizations of five types of engineered organoids with different mutation combinations of five driver genes (APC, SMAD4, KRAS, TP53, and PIK3CA) showed that sequential introductions of all five driver mutations could induce enhanced activation of more hallmark signatures, tending to cancer. Comparative analysis of engineered organoids and corresponding CRC tissues revealed sequential introduction of key mutations could continually shorten the biological distance from engineered organoids to CRC tissues. Nevertheless, there still existed substantial biological gaps between the engineered organoid even with five key mutations and CRC samples. Thus, we proposed an integrative strategy to prioritize gene cascading paths for shrinking biological gaps between engineered organoids and CRC tissues. Our results not only recapitulated the well-known adenoma–carcinoma sequence model (e.g., AKST-organoid with driver mutations in APC, KRAS, SMAD4, and TP53), but also provided potential paths for delineating alternative pathogenesis underlying CRC populations (e.g., A-organoid with APC mutation). Our strategy also can be applied to both organoids with more mutations and other cancers, which can improve and innovate mechanism across cancer patients for drug design and cancer therapy.

Contribution to the study of frontal sinus familial similarity based on genealogically documented individuals (Bohemia, 19th to 20th centuries)

The issue of the influence of biological relatedness on frontal sinus patterns is still the subject of discussion. Research possibilities worldwide are however limited by the lack of genealogically documented skeletal remains. This study presents the results of analyses of seven identified 19th-20th century skulls from two families, discovered in the collections of the Hrdlička Museum of Man. Anteroposterior X-rays were created and the morphology of the frontal sinuses was evaluated using two approaches: A) a simple visual assessment indicating shared or similar features; and B) calculation of the degree of similarity based on a scoring system. With both approaches, the results of family relationship assessments were best reflected in the first family, between individuals with the smallest degree of biological distance. In the second family, which had more distant relationships compared to the first, the positive relationship between biological distance and degree of similarity was not clearly apparent. Although this is a small sample with a small number of generations, our findings support the conclusions of previous studies, i.e. that the degree of similarity between individuals decreases with their increasing biological distance.

Reestablishment of Biological Distance in a Gummy Smile: Case Report

Reestablishment of Biological Distance in a Gummy Smile: Case Report

Identification of candidate disease genes in patients with common variable immunodeficiency

BackgroundCommon variable immunodeficiency (CVID), the most prevalent form of primary immunodeficiency (PID), is characterized by hypogammaglobulinemia and recurrent infections. Understanding protein‐protein interaction (PPI) networks of CVID genes and identifying candidate CVID genes are critical steps in facilitating the early diagnosis of CVID. Here, the aim was to investigate PPI networks of CVID genes and identify candidate CVID genes using computation techniques.MethodsNetwork density and biological distance were used to study PPI data for CVID and PID genes obtained from the STRING database. Gene expression data of patients with CVID were obtained from the Gene Expression Omnibus, and then Pearson’s correlation coefficient, a PPI database, and Kyoto Encyclopedia of Genes and Genomes were used to identify candidate CVID genes. We then evaluated our predictions and identified differentially expressed CVID genes.ResultsThe majority of CVID genes are characterized by a high network density and small biological distance, whereas most PID genes are characterized by a low network density and large biological distance, indicating that CVID genes are more functionally similar to each other and closely interact with one other compared with PID genes. Subsequently, we identified 172 CVID candidate genes that have similar biological functions to known CVID genes, and eight genes were recently reported as CVID‐related genes. MYC, a candidate gene, was down‐regulated in CVID duodenal biopsies, but up‐regulated in blood samples compared with levels in healthy controls.ConclusionOur findings will aid in a better understanding of the complex of CVID genes, possibly further facilitating the early diagnosis of CVID.

The anthropological assessment of the Late Roman cemetery at somogyszil-Dögkúti dűlő

Abstract The results of a general anthropological examination of 140 individuals from a late Roman period cemetery at Somogyszil-Dögkút site are presented in this paper. The population had a more or less balanced sex ratio, lived a fundamentally peaceful life suggested by the low frequencey of bone injuries, and according to their morphoscopic traits, they all belonged to the Caucasoid group. Based on the biological distances calculated from selected linear measurements of male crania, the population of Somogyszil-Dögkút proved to be quite similar to several other late Roman period cemeteries in Transdanubia, as well as to some local Avar period series. This raises the possibility of a significant local continuity between the late Roman and late Avar period on this territory, however other potential explanations cannot be ruled out. Some anthropological characteristics of the human skeletal material unearthed from graves oriented differently than the cemetery's norm suggest the presence of immigrants in the community. Their biological background cannot be traced from the present data, however a few skeletal evidence proposes the probability of a Sarmatian origin.

Discriminating among forest communities based on taxonomic, phylogenetic and trait distances

Quantifying the compositional differences among communities is central to answering some of the most challenging questions in community ecology. Traditional species-based estimates of community dissimilarity convey little information regarding the biological heterogeneity of species. More refined phylogenetic- and functional-based measures can improve the understanding of ecological mechanisms that drive species composition. However, a generalized framework, which unifies taxonomic, phylogenetic, and functional information of communities is still lackling. We present a new general framework for assessing the biological dissimilarity among communities based on species frequencies and biological (including taxonomic, phylogenetic, and functional) distances between species. We used the observations collected in a 30-hectare forest plot in northeastern China to illustrate the application of the new approach and its ability to discriminate communities along spatial and environmental gradients. The results suggested that both spatial and environmental gradients play significant roles in driving the species composition of forest communities. Compared with spatial gradients, local environmental conditions had a greater influence. Conclusion: The ability to measure differences among communities, based on species frequency and biological distances is useful for estimating effects of habitat heterogeneity, for understanding the mechanism of community assembly, and for assessing disturbance effects or species invasions at local or global scales. The Avalanche approach presented in this study represents an effective framework for comparing different measures of biological dissimilarity in one compatible system.

Changes in indigenous population structure in colonial Mexico City and Morelos

AbstractThe Spanish conquest and colonization of Mexico had disastrous effects on indigenous people. Disease, coupled with drastic changes in the economic, political, and religious structures, led to an enormous depopulation event throughout the colony of New Spain. What remains unclear in historic and archeological accounts of Spanish colonization in Mexico is the effects of these changes on indigenous population structure and variation. In this study, we use biological distance and population structure analyses of two Mexico City church ossuary samples from the 16th to 17th centuries, as well as a sample of burials from a convent in nearby Morelos, to investigate these relationships at the center of the Spanish colony in Central Mexico. Colonial samples are compared with a large data set of precontact samples from Central Mexico and the surrounding regions, to evaluate changes in population structures. We compare colonial and precontact samples using biological distance analysis and a population structure program commonly applied in genetic analyses and modified for phenotypic data. Our results show that the colonial Mexico City samples are more biologically similar to the precontact samples from Veracruz, Toluca Valley, and West Mexico than to other precontact samples from the Valley of Mexico. The sample from Yecapixtla in Morelos is also most similar to the Veracruz, Toluca Valley, and West Mexico samples but is also somewhat similar to the precontact sample from Morelos and the nearby Oaxaca Valley. Generally, biological similarities among colonial samples and precontact samples do not correlate with geographic proximity or population size but coincide with cultural changes. Our study provides bioarcheological evidence of some degree of population replacement, resulting either from forced migration from surrounding areas for labor or through indigenous alliances with the Spanish conquerors. Our results also show concordance between traditional biodistance analysis and nontraditional analyses employed in population genetics studies.

SA49 - A QUANTITATIVE ANALYSIS OF DISCREPANCIES BETWEEN CANDIDATE GENE AND GENOME-WIDE STUDIES OF COMPLEX TRAITS AND RELATED ENDOPHENOTYPES

Background Candidate gene and genome-wide investigations of complex traits and related endophenotypes are both fundamentally concerned with elucidating the biological pathways underlying individual differences in behavior. However, these two methods have produced disparate literatures and have often reached contradictory conclusions about the genetic architectures of target traits. Thus far, the polarizing attempts to reconcile these discrepancies have been largely rhetorical. In contrast, the present research uses rigorous quantitative methods to evaluate plausible explanations for the current disagreement in the literature: poor measurement and simplistic models in genome-wide studies versus publication bias and methodological errors in candidate gene work. Results aim to aid investigators in parsing previous findings and selecting future research targets. Methods We present closed form representations of the dependencies between statistical power in genome-wide association studies and endophenotype studies, measurement error, and endotype-complex trait associations. The resulting theory is used to critically evaluate the existing candidate gene literature. Additionally, we present novel methods for falsifying gene-by-environment interaction hypotheses in genome-wide samples where the environmental variable is unobserved and apply this method to data from large genome-wide studies of Schizophrenia and Major Depressive Disorder conducted by the Psychiatric Genetics Consortium. Finally, we evaluate the evidence for publication bias in the candidate gene literature as a competing explanation for observed discrepancies. Results Attenuation of true genetic associations in genome-wide studies vis-a-vis those reported in smaller candidate gene studies (regardless of whether caused by measurement error, biological distance, or any combination thereof) is only likely to explain observed discrepancies in the literature when the association between the candidate-gene study trait and the genome-wide association study trait is weak, leaving endophenotype candidate gene researchers in a paradoxical position. Moreover, even after allowing for the possibility of extreme measurement error in genome-wide data, leading candidate gene-by-environment interaction hypotheses are incompatible with recent genome-wide association study findings. Finally, an overwhelming ratio of positive to null findings and the ubiquitous failure to cite mainstream genetics findings suggest that prevalent publication bias and interdisciplinary fragmentation characterize the existing candidate gene literature. Discussion Candidate gene research, especially endophenotype and gene-by-environment interaction literature continue to gain popularity across the behavioral sciences. However, empirical support for the findings these methods have produced is weak. By making common arguments for continuing candidate gene research mathematically precise and then evaluating evidence for their unacknowledged implications, we conclude that neither measurement error, overly-complex or heterogenous phenotyping, nor unmeasured environmental moderators can explain discrepancies between candidate gene and genome-wide findings. Instead, widespread publication bias and false positive findings provide a likely alternative explanation.

Frequency and variability of five non metric dental crown traits in the permanent maxillary dentitions of a racially mixed population from Bengaluru, Karnataka.

Introduction:Evaluation of Tooth Crown non metric traits benefits to assess the biological distance between populations. It is well known that these traits are characterised by a high inter-population differentiation, low sexual dimorphism, and their recording is loaded by relatively small intra and inter observer error. The dental morphological traits are successfully used in the description and explanation of the microevolutionary and ethnogenetic processes. This paper presents the results of the permanent maxillary dentition tooth crown traits differentiation of human populations from Bengaluru.Materials and Methods:The comparative analysis was carried out on the basis of 4 groups for 5 Tooth Crown non metric traits in maxillary permanent dentition using Arizona State University Dental Anthropology System for morphological scoring system of each trait and each score was charted on Osteoware Dental Morphology software.Results:Study analysed 400 dental casts from 4 different ethnic groups. Traits Winging, shovelling, lingual tubercle showed highest expression in Iranians while Cusp of Carabelli's trait expression showed 87% of prevalence in the surveyed group but the Hypocone trait showed the highest expression in Muslims.Conclusion:Traits of the human dentition can be a valuable diagnostic tool for anthropological studies in classifying and characterizing different ethnic groups. According to the results obtained from this study, it can be said that the groups Hindus, Muslims and Christians (Indians) belong to Sundonts, while Iranians fall under sinodonts population group.

Dispersion, colonization and phenotypic structure of prehistoric human populations of the Andes of North-Western Argentina.

In this article we study the phenotypic structure, biological relationships and evolutionary factors that acted on the biological diversity observed in the prehistoric groups that inhabited Northwest Argentina (NWA). The collections used belong to different subareas and periods of the development of this region. In this study 15 metric traits of the skull were used. To achieve the proposed objective, models derived from population genetics, multivariate statistical analysis, geo-referenced map and phenotypic correlation between geographical and biological distances were applied. The total genetic divergence (FST) is 16% and within subregions it varies between 2% and 10%. The correlation (r) between geographic and phenotypic distances among all samples in NWA is 0.3 and within subregions it varies between -0.16 (Quebrada de Humahuaca) and 0.7 (Puna de Jujuy). The analysis of georeferenced data indicates two phenotypic gradients in NWA. The results show a varied evolutionary scenario, characterized by an important population structure produced by a set of evolutionary factors (genetic isolation, non-random mating, effective size and different rates of genetic interaction between subpopulations).

Thermal effects of mobile phones on human auricle region

Mobile phones have become an indispensable utility to modern society, with international use increasing dramatically each year. The GSM signal operates at 900 MHz, 1800 MHz and 2250 MHz, may potentially cause harm to human tissue. Yet there is no in silico model to aid design these devices to protect from causing potential thermal effect. Here we present a model of sources of heating in a mobile phone device with experimental verification during the phone call. We have developed this mobile phone thermal model using first principles on COMSOL® Multiphysics modelling platform to simulate heating effect in human auricle region due to mobile phone use. In particular, our model considered both radiative and non-radiative heating from components such as the lithium ion battery, CPU circuitry and the antenna. The model showed the distribution and effect of the heating effect due to mobile phone use and considered impact of battery discharge rate, battery capacity, battery cathode material, biological tissue distance, antenna radio-wave frequency and intensity. Furthermore, the lithium ion battery heating was validated during experiments using temperature sensors with an excellent agreement between simulated and experimental data (<1% variation). Mobile phone heating during a typical call has also been simulated and compared with experimental infrared thermographic imaging. Importantly, we found that 1800 MHz frequency of data transmission showed the highest temperature increase in the fat/water phantom used in this simulation. We also successfully compared heating distribution in human auricle region during mobile phone use with clinical thermographic images with reasonable qualitative and quantitative agreements. In summary, our model provides a foundation to conceive thermal and other physical effects caused by mobile phone use and allow for the understanding of potential negative health effects thus supporting and promoting personalized and preventive medicine using thermography.

Torus Mandibularis: Etiology and Bioarcheological Utility

Torus mandibularis is a non-metric traitcommonly recorded in bioarcheological investigationand often included in the battery of non-metric traitsused to analyse biological distance among populations.However, there is considerable debate regarding theetiology of the trait, with genetic and environmentalfactors both having been posited as the primary factorin torus development. This study of 498 individuals,drawn from eight archeological samples, investigatesthe variation in torus frequency in different groups asdefined by sample, age, sex, and measures of functionalstress. Frequencies varied significantly among bothsamples and dental attrition categories, supportingthe idea that mandibular tori are a threshold trait,influenced by both genetic and environmental factors.Results of this study suggest the utility of mandibulartori in bioarchaeology may lie outside of biodistanceanalyses that rely on the high heritability quotient ofnon-metric traits to establish population distances.