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Mbonani TM, L'Abbé EN, Ridel AF. Automated reconstruction: Predictive models based on facial morphology matrices. Forensic Sci Int 2024; 359:112026. [PMID: 38677157 DOI: 10.1016/j.forsciint.2024.112026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/29/2024]
Abstract
Forensic Facial Approximation (FFA) has evolved, with techniques advancing to refine the intercorrelation between the soft-tissue facial profile and the underlying skull. FFA has become essential for identifying unknown persons in South Africa, where the high number of migrant and illegal labourers and many unidentified remains make the identification process challenging. However, existing FFA methods are based on American or European standards, rendering them inapplicable in a South African context. We addressed this issue by conducting a study to create prediction models based on the relationships between facial morphology and known factors, such as population affinity, sex, and age, in white South African and French samples. We retrospectively collected 184 adult cone beam computed tomography (CBCT) scans representing 76 white South Africans (29 males and 47 females) and 108 French nationals (54 males and 54 females) to develop predictive statistical models using a projection onto latent structures regression algorithm (PLSR). On training and untrained datasets, the accuracy of the estimated soft-tissue shape of the ears, eyes, nose, and mouth was measured using metric deviations. The predictive models were optimized by integrating additional variables such as sex and age. Based on trained data, the prediction errors for the ears, eyes, nose, and mouth ranged between 1.6 mm and 4.1 mm for white South Africans; for the French group, they ranged between 1.9 mm and 4.2 mm. Prediction errors on non-trained data ranged between 1.6 mm and 4.3 mm for white South Africans, whereas prediction errors ranging between 1.8 mm and 4.3 mm were observed for the French. Ultimately, our study provided promising predictive models. Although the statistical models can be improved, the inherent variability among individuals restricts the accuracy of FFA. The predictive validity of the models was improved by including sex and age variables and considering population affinity. By integrating these factors, more customized and accurate predictive models can be developed, ultimately strengthening the effectiveness of forensic analysis in the South African region.
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Affiliation(s)
- Thandolwethu Mbali Mbonani
- University of Pretoria, Department of Anatomy, Faculty of Health Sciences, Tswelopele Building, Private Bag X323, Prinshof 349-Jr, Pretoria 0084, South Africa.
| | - Ericka Noelle L'Abbé
- University of Pretoria, Department of Anatomy, Faculty of Health Sciences, Tswelopele Building, Private Bag X323, Prinshof 349-Jr, Pretoria 0084, South Africa.
| | - Alison Fany Ridel
- University of Pretoria, Department of Anatomy, Faculty of Health Sciences, Tswelopele Building, Private Bag X323, Prinshof 349-Jr, Pretoria 0084, South Africa.
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Davidson CL, de Klerk J, Matejovsky Z, Fabris-Rotelli I, Uys A. Metric evaluation of the anterior nasal spine to estimate sex and population group in South African individuals. Int J Legal Med 2024; 138:1117-1137. [PMID: 38010514 PMCID: PMC11003921 DOI: 10.1007/s00414-023-03130-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/12/2023] [Indexed: 11/29/2023]
Abstract
INTRODUCTION The anterior nasal spine is a pointed, midline projection of the maxilla. This bony structure dictates the overlying soft tissues providing the phenotypic features of the nose and upper lip and determines the differences in the mid-face morphology. Little data is available on the metric features of the Anterior nasal spine (ANS). This study aimed to perform metric evaluations of the ANS of white and black South African males and females to ascertain if morphological variations exist and if the differences are viable for the use in sex and population identification. MATERIALS AND METHODS The sample included 100 CBCT images for each population and sex group. Linear and angular measurements of the ANS were recorded in both the sagittal and axial planes. RESULTS Classification decision trees (pruned) were fitted to ascertain the relationship between population group, sex and the ANS measurements including and excluding age. For population group, all the ANS measurements were statistically significant for females but in males, all the ANS measurements were significant when performed individually. However, when fitted to the classification tree, Sagittal 2 did not show any statistical significance. When considering sex, only 2 of the ANS measurements (Sagittal 2 and Axial 1) were found to be significant. The results did not differ significantly when comparing the decision trees including and excluding age. CONCLUSIONS White South African individuals presented with a longer ANS that produced a more acute angle whereas black South African individuals presented with a shorter ANS and a more obtuse angle. Additionally, males presented with a longer ANS compared to females. ANS measurements were found to be more relevant for population discernment than for sex.
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Affiliation(s)
- Christy Lana Davidson
- Department of Oral and Maxillofacial Pathology, School of Dentistry, Faculty of Health Sciences, University of Pretoria, PO Box 1266, Pretoria, 0001, South Africa.
| | - Johan de Klerk
- Department of Oral and Maxillofacial Pathology, School of Dentistry, Faculty of Health Sciences, University of Pretoria, PO Box 1266, Pretoria, 0001, South Africa
| | - Zina Matejovsky
- Department of Oral and Maxillofacial Pathology, School of Dentistry, Faculty of Health Sciences, University of Pretoria, PO Box 1266, Pretoria, 0001, South Africa
| | - Inger Fabris-Rotelli
- Department of Statistics, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
| | - Andre Uys
- Department of Anatomy, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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Liebenberg L, L'Abbé EN, Stull KE. Exploring cranial macromorphoscopic variation and classification accuracy in a South African sample. Int J Legal Med 2024:10.1007/s00414-024-03230-2. [PMID: 38622313 DOI: 10.1007/s00414-024-03230-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/03/2024] [Indexed: 04/17/2024]
Abstract
To date South African forensic anthropologists are only able to successfully apply a metric approach to estimate population affinity when constructing a biological profile from skeletal remains. While a non-metric, or macromorphoscopic approach exists, limited research has been conducted to explore its use in a South African population. This study aimed to explore 17 cranial macromorphoscopic traits to develop improved methodology for the estimation of population affinity among black, white and coloured South Africans and for the method to be compliant with standards of best practice. The trait frequency distributions revealed substantial group variation and overlap, and not a single trait can be considered characteristic of any one population group. Kruskal-Wallis and Dunn's tests demonstrated significant population differences for 13 of the 17 traits. Random forest modelling was used to develop classification models to assess the reliability and accuracy of the traits in identifying population affinity. Overall, the model including all traits obtained a classification accuracy of 79% when assessing population affinity, which is comparable to current craniometric methods. The variable importance indicates that all the traits contributed some information to the model, with the inferior nasal margin, nasal bone contour, and nasal aperture shape ranked the most useful for classification. Thus, this study validates the use of macromorphoscopic traits in a South African sample, and the population-specific data from this study can potentially be incorporated into forensic casework and skeletal analyses in South Africa to improve population affinity estimates.
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Affiliation(s)
- Leandi Liebenberg
- Department of Anatomy, University of Pretoria, Private Bag x323, Arcadia, 0007, South Africa.
- Forensic Anthropology Research Centre, University of Pretoria, Arcadia, South Africa.
| | - Ericka N L'Abbé
- Department of Anatomy, University of Pretoria, Private Bag x323, Arcadia, 0007, South Africa
| | - Kyra E Stull
- Department of Anatomy, University of Pretoria, Private Bag x323, Arcadia, 0007, South Africa
- Department of Anthropology, University of Nevada, Reno, USA
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Bothma NP, L'abbé EN, Liebenberg L. Evaluating postcranial macromorphoscopic traits to estimate population variation among modern South Africans. Forensic Sci Int 2024; 356:111954. [PMID: 38382241 DOI: 10.1016/j.forsciint.2024.111954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/20/2023] [Accepted: 01/31/2024] [Indexed: 02/23/2024]
Abstract
Population overlap and the variation within and among populations have been globally observed but is often difficult to quantify. To achieve this, numerous different methods need to be explored and validated to assist with the creation of an accurate biological profile. The current lack of databases for postcranial macromorphoscopic traits indicates the need to further investigate if the method can be employed repeatably in a forensic context. The current study aimed to assess the prevalence of eleven postcranial macromorphoscopic traits in a South African sample. A total of 271 postcrania of adult black, coloured, and white South Africans were assessed. The intra- and inter-observer agreement ranged from fair to almost perfect except for the accessory transverse foramen of C1, which had poor agreement between observers. Only seven traits differed significantly between at least two of the groups. Univariate and multivariate random forest models were created to test the positive predictive performance of the traits to classify population affinity. The classification accuracies for the univariate models ranged from 33.3% to 53.0% and ranged from 54.6% to 62.1% for the multivariate models. Based on the variable importance, the traits assessing spinous process bifurcation were the most discriminatory variables. The results indicate that the postcranial MMS approach does not outperform current methods employed to estimate population affinity. Further research needs to be done for the method to have practical applicability for medicolegal casework in South Africa.
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Affiliation(s)
- N P Bothma
- University of Pretoria, Department of Anatomy, Pretoria, South Africa, Private Bag x323, Gezina 0031, South Africa.
| | - E N L'abbé
- University of Pretoria, Department of Anatomy, Pretoria, South Africa, Private Bag x323, Gezina 0031, South Africa
| | - L Liebenberg
- University of Pretoria, Department of Anatomy, Pretoria, South Africa, Private Bag x323, Gezina 0031, South Africa
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Voegt C, Gunston G, Nortje M, Sealy JC, He L, le Roux P, Namayega C, Gibbon VE. Bilateral hip dysplasia in a South African male: A case study from the 17-18th century. INTERNATIONAL JOURNAL OF PALEOPATHOLOGY 2023; 42:27-33. [PMID: 37527585 DOI: 10.1016/j.ijpp.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/03/2023]
Abstract
OBJECTIVE To identify, critically analyse and describe severe bilateral skeletal pathology involving the ossa coxae of an individual from historic era Cape Town. MATERIALS A single individual from the University of Cape Town's Human Skeletal Repository was analysed under research approval (HREC# 035/2021). METHODS An osteobiography was constructed, radiocarbon dating and isotopic analyses were conducted. Pathological description and contextualised disability analyses followed, along with differential diagnosis. The pelvis and femora were visualised macroscopically and radiographically. RESULTS This individual was a non-European middle-aged adult male who lived in the 17-18th centuries CE. Morphological changes showed hypoplastic hips with collapsed femoral heads and neoacetabulae. A diagnosis of developmental dysplasia of the hips (DDH) was made. Then a contextualised disability analysis including consideration of the clinical and functional impacts of the condition were applied. No signs of maltreatment, physiological stress or persistent infections were present. His bones were well developed, illustrating mobility and use. CONCLUSIONS He developed DDH early in life and lived through adulthood, and his strong, healthy bones suggest resilience, some mobility and contribution to society through less physically demanding tasks. SIGNIFICANCE Value for palaepathological analyses to inform and understand disability and culturally significant health mediation to offer a more objective interpretation and improve understanding of past people. It expands our understanding of the presence of DDH globally and in Africa and provides insight into disease impact for individuals with bilateral expression. SUGGESTIONS FOR FUTURE RESEARCH Further contextual research is required. LIMITATIONS Poor scene recovery hindered in-depth care analysis and interpretation of the condition.
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Affiliation(s)
- Chelsey Voegt
- Division of Clinical Anatomy and Biological Anthropology, Department of Human Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Geney Gunston
- Division of Clinical Anatomy and Biological Anthropology, Department of Human Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Marc Nortje
- Department of Orthopaedic Surgery, University of Cape Town, Vincent Pallotti and Kingsbury Hospitals, Cape Town, South Africa
| | - Judith C Sealy
- Department of Archaeology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Letian He
- School of History and Culture, Department of Archaeology and Museology, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Petrus le Roux
- Department of Geological Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Catherine Namayega
- Medical Imaging Inferencing and Distributed Diagnostics laboratory (Mi2d2), Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
| | - Victoria E Gibbon
- Division of Clinical Anatomy and Biological Anthropology, Department of Human Biology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa.
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Naidu L, Sibiya LA, Aladeyelu OS, Rennie CO. Anatomical landmarks for localisation of the anterior ethmoidal artery: a combined radiological and cadaveric (endoscopic) study. Surg Radiol Anat 2023; 45:545-554. [PMID: 36939871 PMCID: PMC10129993 DOI: 10.1007/s00276-023-03122-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/22/2023] [Indexed: 03/21/2023]
Abstract
PURPOSE The anterior ethmoidal artery is a major surgical landmark that is susceptible to iatrogenic injury during surgery of the anterior ethmoidal sinus, frontal sinus, and skull base. The present study aimed to define the location of the anterior ethmoidal artery in relation to specific anatomical landmarks using radiological imaging and endoscopic dissection. METHODS Eighty-six anterior ethmoidal arteries were assessed using computed tomography scans (bilateral analyses) and forty anterior ethmoidal arteries were assessed using cadaveric specimens (bilateral analyses). The skull base, anterior nasal spine, anterior axilla of the middle turbinate, and nasal axilla were morphometrically analysed to determine their reliability as anterior ethmoidal artery landmarks. RESULTS Distances to the skull base, anterior nasal spine, and nasal axilla displayed statistically significant differences between sexes and sides (p < 0.05). All landmarks demonstrated excellent reliability as anatomical landmarks for the localisation of the anterior ethmoidal artery, radiologically and endoscopically (ICC values ranged from 0.94 to 0.99). CONCLUSION The middle turbinate axilla was the most reliable landmark, due to the lack of statistically significant differences according to sex and laterality, and the high inter-rater agreement between measurements. Anatomical knowledge of variations and relationships observed in the present study can be applied to surgeries of the anterior ethmoidal sinus, frontal sinus, and skull base to improve localisation of the anterior ethmoidal artery, preoperatively and intraoperatively, and avoid iatrogenic injury of the vessel.
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Affiliation(s)
- Livashin Naidu
- Discipline of Clinical Anatomy, School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban, 4001, KwaZulu-Natal, South Africa. .,Department of Human Biology and Integrated Pathology, School of Medicine, Faculty of Health Sciences, Nelson Mandela University-Missionvale Campus, Gqeberha, 6059, Eastern Cape, South Africa.
| | - Lindokuhle A Sibiya
- Discipline of Otorhinolaryngology-Head and Neck Surgery, School of Clinical Medicine, College of Health Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, KwaZulu-Natal, South Africa
| | - Okikioluwa S Aladeyelu
- Discipline of Clinical Anatomy, School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban, 4001, KwaZulu-Natal, South Africa
| | - Carmen O Rennie
- Discipline of Clinical Anatomy, School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban, 4001, KwaZulu-Natal, South Africa
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Prevalence of Oral Exostoses in Northern China During the Past Six Millennia-From a Sex and Age Perspective. J Craniofac Surg 2023; 34:768-771. [PMID: 36002926 DOI: 10.1097/scs.0000000000008956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022] Open
Abstract
This study is intended to investigate oral exostoses of 5 sample populations, spanning over 6000 years, from the same region of Northern China, to determine the significance of sex and age on the development of oral exostoses during each time period. The samples analyzed were 306 dry jaws from human skeletons, which were excavated from 4 archeological sites: Banpo (6700-5600 y BP), Shaolingyuan (3000 y BP), Shanren (2200 y BP), and Chang'an (1000-1300 y BP), as well as the modern Xi'an district. The sex and the age of the samples at death were estimated. The degree of buccal exostosis (BE), torus mandibularis (TM), and torus palatinus (TP) and the TP shape were recorded. The results showed BEs in the Banpo and Chang'an regions, TMs in the Banpo region were more often diagnosed in males than in females. Conversely, females in Shaolingyuan showed a higher prevalence and severity of TM than that in males. The occurrence of BEs in the Shanren and Xi'an regions, TMs in the Banpo, Chang'an, and Xi'an regions, as well as TPs in the Banpo region significantly increased with age at death. In conclusion, sex differences and increasing trends with age in relation to oral exostoses were found in samples from Northern China during the past six millennia.
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Evaluation of the obturator foramen as a sex assessment trait. Forensic Sci Med Pathol 2022:10.1007/s12024-022-00514-0. [PMID: 35960449 DOI: 10.1007/s12024-022-00514-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2022] [Indexed: 10/15/2022]
Abstract
Correctly assessing sex from skeletal remains is one of the main elements of creating a biological profile. Many traits allow for this, the obturator foramen being one. However, research on its accuracy has provided mixed results. This study examines the obturator foramen using a 5-point grading scale to assess the degree of sexual dimorphism in four known age and sex skeletal collections from the UK and South Africa. Overall, sexual dimorphism was found in the obturator foramen when using the new scoring system; however, accuracies for correct sex classification ranged from ~ 46 to ~ 75%. Considering its wide range in accuracy rates across the four samples and difficulty in identifying the subtle changes in morphology, the obturator foramen should only be used as part of a multifactorial assessment of sex.
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Nonmetric Variants of Anatolian Crania: A Preliminary Study. J Craniofac Surg 2022; 33:2677-2681. [PMID: 35894516 DOI: 10.1097/scs.0000000000008796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 04/24/2022] [Indexed: 11/26/2022] Open
Abstract
Analysis of nonmetric cranial variants has been essential for identifying the human population through osteologic analysis and genetic affinities. This study aimed to examine the nonmetric cranial variants to evaluate differences among sex and side correlations in Anatolian dry skulls. This study was carried out on 50 Anatolian adult dry human skulls (22 males, 28 females) with suitable features (nonfractured and/or with necessary features) out of a total of 97 dry skulls. After sex analysis, each skull was photographed from the norma frontalis, lateralis, inferior, and superior. Eleven nonmetrical cranial variants were investigated. The cranial variants and side incidences were analyzed to determine their sex differences and interside correlations. After the classification, traits were marked as "present" or "absent" on the charts. Some variants in female crania were seen more frequently than in males. Most of the variants such as the supraorbital notch, infraorbital and zygomaticofacial foramen, showed high correlations between the right and left sides. Overall, there were no statistically significant sex or side differences found in the Anatolian crania.
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Pengyue L, Siyuan X, Yi J, Wen Y, Xiaoning L, Guohua G, Shixiong W. ANINet: a deep neural network for skull ancestry estimation. BMC Bioinformatics 2021; 22:550. [PMID: 34763653 PMCID: PMC8588617 DOI: 10.1186/s12859-021-04444-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/12/2021] [Indexed: 11/20/2022] Open
Abstract
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.
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Affiliation(s)
- Lin Pengyue
- College of Information Science and Technology, Northwest University, Xi'an, China
| | - Xia Siyuan
- College of Information Science and Technology, Northwest University, Xi'an, China
| | - Jiang Yi
- College of Information Science and Technology, Northwest University, Xi'an, China
| | - Yang Wen
- College of Information Science and Technology, Northwest University, Xi'an, China
| | - Liu Xiaoning
- College of Information Science and Technology, Northwest University, Xi'an, China.
| | - Geng Guohua
- College of Information Science and Technology, Northwest University, Xi'an, China
| | - Wang Shixiong
- College of Information Science and Technology, Northwest University, Xi'an, China
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Plomp KA, Gestsdóttir H, Dobney K, Price N, Collard M. The composition of the founding population of Iceland: A new perspective from 3D analyses of basicranial shape. PLoS One 2021; 16:e0246059. [PMID: 33556115 PMCID: PMC7870008 DOI: 10.1371/journal.pone.0246059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/12/2021] [Indexed: 11/18/2022] Open
Abstract
The settlement of Iceland in the Viking Age has been the focus of much research, but the composition of the founding population remains the subject of debate. Some lines of evidence suggest that almost all the founding population were Scandinavian, while others indicate a mix of Scandinavians and people of Scottish and Irish ancestry. To explore this issue further, we used three-dimensional techniques to compare the basicrania of skeletons from archaeological sites in Iceland, Scandinavia, and the British Isles. Our analyses yielded two main results. One was that the founding population likely consisted of roughly equal numbers of Scandinavians and people from the British Isles. The other was that the immigrants who originated from the British Isles included individuals of southern British ancestry as well as individuals of Scottish and Irish ancestry. The first of these findings is consistent with the results of recent analyses of modern and ancient DNA, while the second is novel. Our study, therefore, strengthens the idea that the founding population was a mix of Scandinavians and people from the British Isles, but also raises a new possibility regarding the regions from which the settlers originated.
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Affiliation(s)
- Kimberly A. Plomp
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- Department of Archaeology, Classics, and Egyptology, University of Liverpool, Liverpool, United Kingdom
| | | | - Keith Dobney
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- Department of Archaeology, Classics, and Egyptology, University of Liverpool, Liverpool, United Kingdom
- School of Historical and Philosophical Inquiry, University of Sydney, Sydney, NSW, Australia
- Department of Archaeology, University of Aberdeen, Aberdeen, United Kingdom
| | - Neil Price
- Department of Archaeology, University of Aberdeen, Aberdeen, United Kingdom
- Archaeology and Ancient History, Uppsala University, Uppsala, Sweden
| | - Mark Collard
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- * E-mail:
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Depiction of ethnic facial aging by forensic artists and preliminary assessment of the applicability of facial averages. Forensic Sci Int 2020; 313:110353. [PMID: 32559613 DOI: 10.1016/j.forsciint.2020.110353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/06/2020] [Accepted: 05/27/2020] [Indexed: 11/22/2022]
Abstract
Many characteristics of facial aging are common to all. The age of their onset and which characteristics tend to predominate varies among individuals depending on many factors including their genetic makeup, life experiences, environment in which they live, and the regional, ethnic, or socially perceived group to which they belong. Forensic artists are often asked to provide sketches, 2D or 3D digital renderings, or sculptures representative of how an individual may appear at an older age based on a provided photograph, victim or witness description, and/or cranial remains. The challenge escalates when the subject is a member of a regional, ethnic, or other socially perceived group to which the artist has had little or no exposure. We describe aspects of adult facial aging that are of particular relevance to the forensic artist, applicable software tools, and pertinent facial databases, especially those emphasizing non-white populations. We demonstrate that facial averaging offers two key advantages to the artistic portrayal of facial aging: first, the technique requires relatively small reference databases from groups that may present logistical challenges to collect and second, that a facial average provides a useful representation of the gestalt of the age and ethnicity cohort to which a subject belongs. The artist may use an average along with other available information such as photo reference books, eyewitness descriptions, photos of immediate family members, and cranial structure to guide production of a facial composite drawing, digital age progression, or sculpture of the subject in question.
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Dunn RR, Spiros MC, Kamnikar KR, Plemons AM, Hefner JT. Ancestry estimation in forensic anthropology: A review. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/wfs2.1369] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rhian R. Dunn
- Department of Anthropology Michigan State University East Lansing Michigan
| | - Micayla C. Spiros
- Department of Anthropology Michigan State University East Lansing Michigan
| | - Kelly R. Kamnikar
- Department of Anthropology Michigan State University East Lansing Michigan
| | - Amber M. Plemons
- Department of Anthropology Michigan State University East Lansing Michigan
| | - Joseph T. Hefner
- Department of Anthropology Michigan State University East Lansing Michigan
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Cunha E, Ubelaker DH. Evaluation of ancestry from human skeletal remains: a concise review. Forensic Sci Res 2019; 5:89-97. [PMID: 32939424 PMCID: PMC7476619 DOI: 10.1080/20961790.2019.1697060] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 10/03/2019] [Accepted: 11/15/2019] [Indexed: 11/30/2022] Open
Abstract
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.
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Affiliation(s)
- Eugénia Cunha
- National Institute of Legal Medicine and Forensic Sciences, Lisbon, Portugal
- Laboratory of Forensic Anthropology, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Douglas H. Ubelaker
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
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Deformation of the zygomaticomaxillary and nasofrontal sutures during bone-anchored maxillary protraction and reverse-pull headgear treatments: An ex-vivo study. Am J Orthod Dentofacial Orthop 2019; 156:745-757. [PMID: 31784008 DOI: 10.1016/j.ajodo.2018.12.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 12/01/2018] [Accepted: 12/01/2018] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Bone-anchored maxillary protraction (BAMP) is an emerging treatment that involves applying a protraction load to the maxillary bone. Although it is believed that such an approach results in better sutural separation, this has not been investigated. This study aimed to assess and compare the deformation of 1 circumaxillary suture (zygomaticomaxillary suture [ZMS]) and 1 facial suture (nasofrontal suture [NFS]) during BAMP and reverse-pull headgear (RPHG) treatment. METHODS The study was performed ex vivo on 15 pig heads. Miniplates were placed in the maxillary bone and the body of the mandible. A molar tube was bonded to the maxillary first molars. Six single-element strain gauges and 3 differential variable reluctance transducers were installed across the ZMS and NFS bilaterally. Each head underwent BAMP and RPHG unilaterally and bilaterally. RESULTS In unilateral experiments, both BAMP and RPHG resulted in tension on the ipsilateral ZMS and NFS and compression on the contralateral side, with higher magnitude in the BAMP group. In bilateral experiments, both modalities resulted in tension at the ZMS, with higher magnitude in the BAMP group. Deformation of the NFS was different between the 2 groups: tension in majority of the BAMP and compression in most of the RPHG heads. CONCLUSIONS Our study shows a higher magnitude of sutural separation in BAMP than in RPHG. The pattern of sutural deformation is consistent with a forward displacement of the midface in BAMP compared with an upward and backward rotation in the RPHG. Rotation of the maxilla was also present in some of the subjects who underwent BAMP.
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Zhang Q, Zhang Q, Yang S, Dechow PC, Zhu H, Yeh HY, Wang Q. Divided zygoma in Holocene human populations from Northern China. Am J Hum Biol 2019; 31:e23314. [PMID: 31456277 PMCID: PMC6916319 DOI: 10.1002/ajhb.23314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 07/16/2019] [Accepted: 08/13/2019] [Indexed: 12/23/2022] Open
Abstract
Objectives Divided zygoma (DZ) occurs in contemporaneous human populations, with the highest incidences in people from East Asia and Southern Africa. The present study examines the prevalence and variation of this condition in the Holocene populations of Northern China for the first time. Methods In this study, 1145 skulls from various human populations living in Northern China from the Neolithic Age to recent dynasties (5000‐300 years BP) were examined. Specifically, cranial measurements and a CT scan were conducted to quantify craniofacial morphology. Results Fifteen skulls were identified with DZ, revealing an overall prevalence of 1.3% in the collection, while it was determined to be higher in North Asian and Northeast Asian regional groups. In skulls with unilateral DZ, the superior division of the zygoma was generally slender, while the inferior division of the zygoma was more robust. In skulls with bilateral DZ, the maxillae were generally more laterally extended. Moreover, unilateral DZ skulls displayed differences in cortical bone thickness between two sides of the facial skeleton. Discussion In context, the distribution pattern within these data points toward a greater prevalence of the DZ phenotype in North and Northeast Asian regional groups, suggesting a hypothesis that the DZ trait is more frequent in populations characterized by flat and broad faces. Accordingly, further studies into the DZ condition will deepen our understanding of developments in plasticity, variation, and recent evolution of the human cranium.
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Affiliation(s)
- Qun Zhang
- School of Humanities, Nanyang Technological University, Singapore, Singapore.,School of Archaeology, Jilin University, Jilin, China
| | | | - Shiyu Yang
- School of Archaeology, Jilin University, Jilin, China
| | - Paul C Dechow
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas
| | - Hong Zhu
- School of Archaeology, Jilin University, Jilin, China
| | - Hui-Yuan Yeh
- School of Humanities, Nanyang Technological University, Singapore, Singapore
| | - Qian Wang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas
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Joubert L, Briers N, Meyer A. Evaluation of the Suchey–Brooks age estimation method in a white South African population. Forensic Sci Int 2019; 301:e14-e19. [DOI: 10.1016/j.forsciint.2019.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/09/2019] [Accepted: 05/13/2019] [Indexed: 10/26/2022]
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Agostini G, Holt BM, Relethford JH. Bone functional adaptation does not erase neutral evolutionary information. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:708-729. [DOI: 10.1002/ajpa.23460] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 02/26/2018] [Accepted: 03/01/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Gina Agostini
- Mayo Clinic/ASU Obesity Solutions, School of Human Evolution and Social ChangeArizona State UniversityTempe Arizona
| | - Brigitte M. Holt
- Department of AnthropologyUniversity of Massachusetts AmherstAmherst Massachusetts
| | - John H. Relethford
- Department of AnthropologyState University of New York at OneontaOneonta New York
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19
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Hefner JT. The macromorphoscopic databank. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:994-1004. [DOI: 10.1002/ajpa.23492] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/08/2018] [Accepted: 04/05/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Joseph T. Hefner
- Department of AnthropologyMichigan State UniversityEast Lansing Michigan 48824
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20
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Krüger GC, L’Abbé EN, Stull KE. Sex estimation from the long bones of modern South Africans. Int J Legal Med 2016; 131:275-285. [DOI: 10.1007/s00414-016-1488-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/21/2016] [Indexed: 11/24/2022]
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Plemons A, Hefner JT. Ancestry Estimation Using Macromorphoscopic Traits. Acad Forensic Pathol 2016; 6:400-412. [PMID: 31239915 PMCID: PMC6474543 DOI: 10.23907/2016.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/21/2016] [Accepted: 07/31/2016] [Indexed: 11/12/2022]
Abstract
Anthropologists have a lengthy history using cranial nonmetric traits to assess biological distances between populations. These concepts were adopted by forensic anthropologists to estimate ancestry at the individual level using population-based human variation. However, this method of estimation must adhere to the Daubert guidelines to be applied in the modern court system. To that end, a set of cranial macromorphoscopic traits have been proffered to generate a methodological approach to the estimation of ancestry that can be empirically tested and verified. Additionally, various statistical frameworks, parametric and nonparametric, have been employed to calculate error rates and provide probabilistic statements of the strength of these estimations. Recent studies have further advanced the reliability and validity of macromorphoscopic trait analysis through reference datasets, validation studies, and demonstrable exploration of the complex population histories impacting human variation between and within populations worldwide.
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A morphometric analysis of prognathism and evaluation of the gnathic index in modern humans. HOMO-JOURNAL OF COMPARATIVE HUMAN BIOLOGY 2016; 67:294-312. [DOI: 10.1016/j.jchb.2016.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 04/17/2016] [Indexed: 11/18/2022]
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Liebenberg L, L'Abbé EN, Stull KE. Population differences in the postcrania of modern South Africans and the implications for ancestry estimation. Forensic Sci Int 2015; 257:522-529. [PMID: 26584515 DOI: 10.1016/j.forsciint.2015.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/07/2015] [Accepted: 10/18/2015] [Indexed: 10/22/2022]
Abstract
The cranium is widely recognized as the most important skeletal element to use when evaluating population differences and estimating ancestry. However, the cranium is not always intact or available for analysis, which emphasizes the need for postcranial alternatives. The purpose of this study was to quantify postcraniometric differences among South Africans that can be used to estimate ancestry. Thirty-nine standard measurements from 11 postcranial bones were collected from 360 modern black, white and coloured South Africans; the sex and ancestry distribution were equal. Group differences were explored with analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) test. Linear and flexible discriminant analysis (LDA and FDA, respectively) were conducted with bone models as well as numerous multivariate subsets to identify the model and method that yielded the highest correct classifications. Leave-one-out (LDA) and k-fold (k=10; FDA) cross-validation with equal priors were used for all models. ANOVA and Tukey's HSD results reveal statistically significant differences between at least two of the three groups for the majority of the variables, with varying degrees of group overlap. Bone models, which consisted of all measurements per bone, resulted in low accuracies that ranged from 46% to 63% (LDA) and 41% to 66% (FDA). In contrast, the multivariate subsets, which consisted of different variable combinations from all elements, achieved accuracies as high as 85% (LDA) and 87% (FDA). Thus, when using a multivariate approach, the postcranial skeleton can distinguish among three modern South African groups with high accuracy.
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Affiliation(s)
- Leandi Liebenberg
- Department of Anatomy, University of Pretoria, Arcadia, South Africa; Department of Basic Medical Sciences, University of the Free State, Bloemfontein, South Africa.
| | - Ericka N L'Abbé
- Department of Anatomy, University of Pretoria, Arcadia, South Africa
| | - Kyra E Stull
- Department of Anthropology, Idaho State University, Pocatello, ID, USA
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McDowell JL, Kenyhercz MW, L'Abbé EN. An evaluation of nasal bone and aperture shape among three South African populations. Forensic Sci Int 2015; 252:189.e1-7. [PMID: 25963274 DOI: 10.1016/j.forsciint.2015.04.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 03/02/2015] [Accepted: 04/15/2015] [Indexed: 11/16/2022]
Abstract
Reliable and valid population specific standards are necessary to accurately develop a biological profile, which includes an estimation of peer-reported social identification (Hefner, 2009). During the last 300 years, colonialism, slavery and apartheid created geographic, physical and social divisions of population groups in South Africa. The purpose of this study was to evaluate variation in nasal bone and aperture shape in a modern population of black, white, and coloured South Africans using standard craniometric variables and geometric morphometrics, namely general Procrustes and elliptical Fourier analyses. Fourteen standard landmarks were digitally recorded or computationally derived from 310 crania using a 3D coordinate digitizer for discriminant function, principal components and generalized Procrustes analyses. For elliptical Fourier analysis, outlines of the nasal aperture were generated from standardized photographs. All classification accuracies were better than chance; the lowest accuracies were for coloured and the highest accuracies were for white South Africans. Most difficulties arose in distinguishing coloured and black South African groups from each other. Generally, misclassifications were noted between the sexes within each group rather than among groups, which suggests that sex has less influence on nasal bone and aperture shape than ancestry. Quantifiable variation in shape of the nasal aperture region between white and non-white South African groups was observed.
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Affiliation(s)
- Jennifer L McDowell
- Department of Anatomy, University of Pretoria, Private Bag x 323, Arcadia 0007, South Africa
| | - Michael W Kenyhercz
- Department of Anthropology, University of Alaska, Fairbanks, AK 99775, United States; Department of Anatomy, University of Tennessee, Knoxville, TN 37996, United States
| | - Ericka N L'Abbé
- Department of Anatomy, University of Pretoria, Private Bag x 323, Arcadia 0007, South Africa.
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Stull KE, Kenyhercz MW, L'Abbé EN. Ancestry estimation in South Africa using craniometrics and geometric morphometrics. Forensic Sci Int 2014; 245:206.e1-7. [PMID: 25459274 DOI: 10.1016/j.forsciint.2014.10.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/04/2014] [Accepted: 10/05/2014] [Indexed: 11/30/2022]
Abstract
Population history and positive assortative mating directs gene flow in such a way that biological differences are recognized among groups. In turn, forensic anthropologists quantify biological differences to estimate ancestry. Some anthropologists argue that highly admixed population groups, such as South African coloureds, cannot achieve acceptable accuracies because within group variance is too large. Whereas ancestry estimation in South Africa has been limited to craniometric data from South African blacks and whites, the current study integrates craniometric and geometric morphometric data from the three largest South African groups. Crania from 377 South African individuals (black=158, white=112, and coloured=107) comprised the sample. Standard measurements were collected and the coordinate data were subjected to Generalized Procrustes Analysis (GPA), which resulted in size-free shape variables (ProCoords). A principal component analysis was used to combine the shape variation captured in the ProCoords (ProCoords PC). Linear discriminant analysis (LDA), using equal priors, stepwise variable selection and leave-one-out cross-validation, was conducted on the ProCoords, the ProCoords PCs, and the traditional craniometric data. The LDA using 18 stepwise selected ProCoords resulted in the highest cross-validated accuracy (89%). Utilization of geometric morphometric data emphasized that the relative location of cranial landmarks was more discriminating than simple linear distances. Regardless of high levels of genetic admixture, South African coloureds are a homogeneous group and morphologically distinct from other contemporaneous South African populations. Furthermore, the present study demonstrated a correspondence between peer-reported race and morphological differences in the crania of black, white, and coloured South Africans.
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Affiliation(s)
- Kyra E Stull
- Department of Anthropology, Idaho State University, 921 South 8th Avenue, Stop 8005, Pocatello, ID 83209, USA.
| | - Michael W Kenyhercz
- Department of Anthropology, University of Tennessee, Knoxville, 250 South Stadium Hall, Knoxville, TN 37996, USA.
| | - Ericka N L'Abbé
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Arcadia 0007, South Africa.
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Small C, Brits DM, Hemingway J. Quantification of the subpubic angle in South Africans. Forensic Sci Int 2012; 222:395.e1-6. [PMID: 22749676 DOI: 10.1016/j.forsciint.2012.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 03/05/2012] [Accepted: 06/04/2012] [Indexed: 11/19/2022]
Abstract
Due to the high crime rate in South Africa, forensic anthropologists are increasingly approached to aid in the identification of skeletonized remains, with sex and population affinity assignment being some of the most critical tasks they face. For over a century, the pelvis has been known to be one of the most sexually dimorphic bones of the human body and the subpubic angle is one of the most accurate, albeit scarcely quantified, features thereof. Hence, the aim of this study was to quantify the size of the subpubic angle and compare it between male and female South Africans of African (black) and European (white) descent. One hundred and forty five (145) pelves were selected, consisting of 68 white (43 male and 25 female) and 77 black South Africans (44 male and 33 female), from the Raymond A. Dart Collection of Human Skeletons housed at the University of the Witwatersrand, Johannesburg, South Africa. Each of the pelves were articulated and placed into a custom built stand for photographing. Measures of the subpubic angle from these digital images were subjected to numerous statistical analyses. Results indicated that significant differences exist between the sexes, as well as between the two population groups. For black individuals it was found that males generally possessed a subpubic angle of 74.9° or less, with larger values being indicative of the female sex. For white individuals, subpubic angles of 81.4° and less indicated males whilst larger values indicated females, with an average accuracy of 86% for both population groups. These results illustrate the advantages of using the subpubic angle to assist in the estimation of sex and population affinity and also reinforce the need for population specific parameters to be applied.
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Affiliation(s)
- Candice Small
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa.
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Sholts SB, Wärmländer SKTS. Zygomaticomaxillary suture shape analyzed with digital morphometrics: reassessing patterns of variation in American Indian and European populations. Forensic Sci Int 2012; 217:234.e1-6. [PMID: 22154439 DOI: 10.1016/j.forsciint.2011.11.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/16/2011] [Accepted: 11/14/2011] [Indexed: 10/14/2022]
Abstract
Typological classification of human zygomaticomaxillary suture (ZMS) shape is often used in forensic assessment of ancestry, following earlier studies reporting higher frequencies of "angled" sutures among American Indians and higher frequencies of "curved" sutures among Caucasians. In this paper we present a new method of digital morphometrics to quantify and compare ZMS shape in 60 American Indian and 60 European crania. Suture outlines were recorded as three-dimensional (3D) contours on digital models of adult male and female crania created with a portable 3D laser scanner. Each contour was represented by about four hundred point coordinates, which were transformed via Fourier analysis into amplitude coefficients suitable for use in linear discriminant analysis. Discriminant functions were created that accurately predicted group membership for 83% of the crania in the sample, after leave-one-out cross-validation. The results were compared with traditional typological classifications based on visual evaluation of ZMS shape, and the contour-based method was found to be more effective than the typological approach. However, the distribution of ZMS types within the two sample groups did not conform to previously reported patterns. This discrepancy indicates that ZMS shape may reflect not only genetic factors, but also environmental factors such as diet and stress. In addition, some evidence for sexual dimorphism in the zygomaticomaxillary complex was observed. Based on these findings, we recommend caution when using ZMS shape analysis in forensic ancestry determination.
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Affiliation(s)
- Sabrina B Sholts
- Department of Integrative Biology, University of California, Berkeley, 3060 Valley Life Sciences Building #3140, Berkeley, CA 94720-3140, USA.
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