Standardization of Postcranial Nonmetric Traits and Their Utility in Ancestry Analysis

Spiros, Micayla C.

doi:10.5744/fa.2018.1031

Cited by 8 publications

(13 citation statements)

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“…This application, ComboMaMD Analytical v.0.1, was built using “shinyapp” and R 3.6.0 , and is freely available at https://www.macromorphoscopictraitanalysis.shinyapps.io/combo_mamd or by contacting the authors for the source code. Scoring protocols follow Hefner and Spiros and are included in the guide. The model allows up to 35 cranial and postcranial MMS variables, and can handle the missing data seamlessly (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Eight cranial and eleven postcranial MMS traits are included in this study (Tables and ). We did not pool scores for bilateral traits or the Accessory Transverse Foramina (ATF), resulting in 27 postcranial scores.…”

Section: Methodsmentioning

confidence: 99%

“…The genomic revolution in the late 1960s signaled the transition from individual traits (anomalies) to a suite of postcranial traits for measuring population relatedness . Although the results of that research suggested “infracranial traits are just as ‘useful’ as cranial traits in nonmetric distance studies” ([28]:406), postcranial trait research nearly halted with a few notable exceptions . Donlon documented the significance of postcranial trait variation in biological distance studies, using them to weigh in on the debate concerning diversity within and among multiple groups.…”

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confidence: 99%

“…Recently, a suite of postcranial traits was devised via definitions, drawings, and, for the first time, an ordinal scoring system . This method reflects not only the call for standardization by the Daubert decision , but also the 2009 National Academy of Sciences (NAS) report on strengthening forensic sciences and the 2016 President’s Council of Advisors on Science and Technology (PCAST) report on forensic science in criminal courts .…”

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confidence: 99%

“…This scoring procedure provides a rigorous data collection protocol for postcranial traits and more accurately defines variations for each character state (i.e., Anterior and Middle Calcaneal Facet & Septal Aperture). Spiros documented frequency distribution differences between American Black and American White samples; however, the application of her scoring protocol to estimate ancestry has not been confirmed and the incorporation of the protocol with cranial MMS traits has not been assessed or quantified. For clarity, we will refer to the cranial and postcranial variables used in this study as macromorphoscopic (MMS) traits.…”

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confidence: 99%

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Ancestry Estimation Using Cranial and Postcranial Macromorphoscopic Traits

Spiros

Hefner

2019

Journal of Forensic Sciences

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Ancestry estimation methods using macromorphoscopic (MMS) traits commonly focus exclusively on cranial morphology.The objective of this study was to demonstrate the value of postcranial MMS traits, highlighting a combined cranial/postcranial trait approach to ancestry estimation using quadratic discriminant function and a variety of machine learning classification models including artificial neural networks (aNN), random forest models, and support vector machine. Eight cranial and eleven postcranial MMS traits were collected from the Terry and Bass Skeletal Collections (American Black = 81; American White = 173). Our classification models using cranial and postcranial traits correctly classified 88-92% of the sample, improving classification accuracies by nearly fifteen percent over models relying exclusively on cranial data. These same results demonstrate the importance of a multivariate statistical framework incorporating cranial and postcranial data and the nearly unlimited potential of machine learning models to improve the accuracy of ancestry estimates over traditional methods of analysis. To facilitate implementation in casework, one of the more robust models (aNN) is incorporated into a web-based application, Combo-MaMD Analytical, to facilitate cranial and postcranial MMS traits analysis for ancestry estimation.

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Section: Discussionmentioning

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Section: Methodsmentioning

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Ancestry Estimation Using Cranial and Postcranial Macromorphoscopic Traits

Spiros

Hefner

2019

Journal of Forensic Sciences

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Infracranial versus cranial nonmetric traits and mtDNA data in the study of genetic divergence of human populations

Movsesian

Vagner-Sapukhina

2021

Intl J of Osteoarchaeology

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Although cranial and dental nonmetric traits have proven to be reliable proxies for genetic data, the usefulness of infracranial nonmetric traits as phenetic markers in population affinity studies remains unclear. Our aim was to analyze infracranial and cranial nonmetric trait frequencies in the same samples in comparison with genetic data to determine the value of infracranial nonmetric traits in assessing genetic relationships among populations. We examined the frequencies of 25 cranial and 16 infracranial nonmetric traits in seven adult osteological samples from different regions of northern Eurasia (northern Russians, indigenous populations of Volga-Ural region, Buryats, and Yupik) and the data on mitochondrial DNA polymorphisms in the same ethnic groups. The biological distance between each pair of samples was estimated using the Smith's mean measure of divergence (MMD) for nonmetric traits and Cavalli-Sforza distance measure for mtDNA data. Mantel correlations were calculated between two matrices of mean measures of divergence (MMD) distances, and a multidimensional scaling (MDS) procedure was applied to each matrix. The Mantel test showed a strong correlation between the two nonmetric distance matrices. The three-dimensional spatial representations of each matrix revealed similar patterns of intergroup differences. On both nonmetric MDS maps, the sample locations roughly reflected the geographic separation of the groups, with the exception of northern Russians, who were grouped with Volga-Ural populations.Comparison of our results with those obtained from genetic data confirmed that both sets of nonmetric traits provide reliable genetic affinities among the samples. The association of northern Russians with the Volga-Ural groups can be explained by their genetic background. Our findings show that infracranial nonmetric traits can be successfully used as phenetic markers to define a population's affinity and divergence, particularly in cases where only infracranial bones are available for study.

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Ancestry estimation in forensic anthropology: A review

Dunn

Spiros

Kamnikar

et al. 2020

WIREs Forensic Science

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Forensic anthropologists assist law enforcement agencies and medical examiner's offices with investigations involving human remains, providing insight into trauma analysis, the establishment of postmortem interval, and the estimation of biological profile data. Ancestry is considered one of the more difficult aspects of the biological profile, due in large part to the complicated relationship between skeletal morphology and social constructs. The methods used to estimate ancestry rely on the correlation between skeletal morphology, geographic origin, and an individual's social race. While there is a well‐documented contemptible history associated with the development of ancestry estimation methods in biological anthropology, many of the more traditional, now antiquated, methods are still used in some laboratories. The push to improve the framework within which ancestry data are analyzed requires validation and reassessment for each method in addition to the development of novel approaches utilizing modern technological advances. An array of software programs designed to aid in ancestry estimation is available. These advances do not signal the end of ancestry‐related research. Indeed, several areas seemingly stagnated by tradition and time require further study through more than simply review and rarefaction. The future of ancestry estimation research centers on: (a) abandoning the trait list approach, (b) rejecting the three‐group model, (c) establishing larger and more representative reference data, (d) assessing the utility of mixed method models, and (e) developing new statistical approaches and updating current software tools. This article is categorized under: Forensic Anthropology > Ancestry Determination Forensic Medicine > Historical Perspectives Forensic Anthropology > Anthropology in Mass Disaster & War Crime Contexts

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Standardization of Postcranial Nonmetric Traits and Their Utility in Ancestry Analysis

Cited by 8 publications

References 0 publications

Ancestry Estimation Using Cranial and Postcranial Macromorphoscopic Traits

Ancestry Estimation Using Cranial and Postcranial Macromorphoscopic Traits

Infracranial versus cranial nonmetric traits and mtDNA data in the study of genetic divergence of human populations

Ancestry estimation in forensic anthropology: A review

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