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McCrary T, Hughes T, Brook AH, Paul KS. Mirror, mirror? An evaluation of identical twin mirroring in tooth crown morphology. Anat Rec (Hoboken) 2024; 307:3102-3119. [PMID: 38372073 DOI: 10.1002/ar.25408] [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: 12/30/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
It has been estimated that 25% of monozygotic ("identical") twin pairs exhibit reverse asymmetry (RA) or "mirroring" of minor anatomical features as a result of delayed zygote division. Here, we examine whether identical twin mirroring accounts for patterns of dental asymmetry in a sample of monozygotic and dizygotic ("fraternal") twins. We focus on crown morphology to approach the following question: is there an association between dental RA frequency and twin type suggestive of the presence of mirror image twins in our sample? Data were collected from 208 deciduous and 196 permanent dentitions of participants of the University of Adelaide Twin Study using Arizona State University Dental Anthropology System standards. RA frequencies were compared across morphological complexes (deciduous, permanent), twin types (monozygotic, dizygotic), and traits. Fisher's exact tests were performed to formally evaluate the association between twin type and dental RA. Across the entire dataset, RA rates failed to exceed 8% for any twin type. In monozygotic twins, deciduous mirroring totaled 5.3% of observed cases, while permanent mirroring totaled 7.8% of observed cases. We found no statistically significant association between RA and twin type for any morphological character (p-value range: 0.07-1.00). Our results suggest the timing of monozygotic twin division does not explain the structure of asymmetry for our morphology dataset and that published estimates of identical twin mirroring rates may be inflated or contingent upon phenotype. Instead, rates reported for this sample more closely align with the proposed etiology of this condition.
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Affiliation(s)
- Tess McCrary
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
- University of Tennessee Health Science Center, College of Dentistry, Memphis, Tennessee, USA
| | - Toby Hughes
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia
| | - Alan H Brook
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Kathleen S Paul
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
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Harripershad M, Theye CEG, Ridel AF, Liebenberg L. Cranial fluctuating asymmetry and its relationship with non-specific physiological stress indicators in a contemporary South African cadaveric skeletal sample. INTERNATIONAL JOURNAL OF PALEOPATHOLOGY 2024; 46:50-61. [PMID: 39079279 DOI: 10.1016/j.ijpp.2024.07.004] [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: 06/19/2023] [Revised: 06/13/2024] [Accepted: 07/14/2024] [Indexed: 08/25/2024]
Abstract
OBJECTIVES Biological anthropologists frequently explore skeletal asymmetry, together with population health and disease. Given the conflicting findings in existing literature, this study aimed to clarify whether an association exists in a South African sample. MATERIALS Dry bone and cranial micro-focus X-ray Computed Tomography (micro-XCT) scans of 115 South African individuals were assessed. METHODS Fluctuating asymmetry (FA) indices were calculated from interlandmark distances, and the frequency of four types of non-specific signs of physiological stress were documented to explore the relationship between FA and disease. RESULTS Black South Africans did not exhibit a high FA index; however, they had the highest prevalence of non-specific signs of physiological stress. However, no significant correlations were detected between FA indices and pathological lesions. CONCLUSION No correlation was observed between FA and populations from different socio-economic backgrounds. However, individuals of lower socio-economic status (SES) demonstrated a greater prevalence of non-specific signs of physiological stress. SIGNIFICANCE This research suggests that skeletal indicators of stress may be a suitable biological marker for assessing differences in SES among population groups, while indicating that levels of cranial FA is an inadequate biological marker. LIMITATIONS Possible limitations may include measurement error, and the lack of information on the life history and medical records of individuals in this sample. SUGGESTIONS FOR FURTHER RESEARCH Future research should include a larger sample with more South African groups, and should evaluate the potential association among age, FA, and expression of skeletal markers of disease.
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Affiliation(s)
- M Harripershad
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Gezina, Pretoria 0031, South Africa.
| | - C E G Theye
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Gezina, Pretoria 0031, South Africa.
| | - A F Ridel
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Gezina, Pretoria 0031, South Africa.
| | - L Liebenberg
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Private Bag x323, Gezina, Pretoria 0031, South Africa.
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Hanegraef H, Spoor F. Maxillary morphology of chimpanzees: Captive versus wild environments. J Anat 2024; 244:977-994. [PMID: 38293709 PMCID: PMC11095307 DOI: 10.1111/joa.14016] [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: 03/29/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/01/2024] Open
Abstract
Morphological studies typically avoid using osteological samples that derive from captive animals because it is assumed that their morphology is not representative of wild populations. Rearing environments indeed differ between wild and captive individuals. For example, mechanical properties of the diets provided to captive animals can be drastically different from the food present in their natural habitats, which could impact cranial morphology and dental health. Here, we examine morphological differences in the maxillae of wild versus captive chimpanzees (Pan troglodytes) given the prominence of this species in comparative samples used in human evolution research and the key role of the maxilla in such studies. Size and shape were analysed using three-dimensional geometric morphometric methods based on computed tomography scans of 94 wild and 30 captive specimens. Captive individuals have on average larger and more asymmetrical maxillae than wild chimpanzees, and significant differences are present in their maxillary shapes. A large proportion of these shape differences are attributable to static allometry, but wild and captive specimens still differ significantly from each other after allometric size adjustment of the shape data. Levels of shape variation are higher in the captive group, while the degree of size variation is likely similar in our two samples. Results are discussed in the context of ontogenetic growth trajectories, changes in dietary texture, an altered social environment, and generational differences. Additionally, sample simulations show that size and shape differences between chimpanzees and bonobos (Pan paniscus) are exaggerated when part of the wild sample is replaced with captive chimpanzees. Overall, this study confirms that maxillae of captive chimpanzees should not be included in morphological or taxonomic analyses when the objective is to characterise the species.
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Affiliation(s)
- Hester Hanegraef
- Centre for Human Evolution ResearchNatural History MuseumLondonUK
| | - Fred Spoor
- Centre for Human Evolution ResearchNatural History MuseumLondonUK
- Department of Human OriginsMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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Chen YC, Tiego J, Segal A, Chopra S, Holmes A, Suo C, Pang JC, Fornito A, Aquino KM. A multiscale characterization of cortical shape asymmetries in early psychosis. Brain Commun 2024; 6:fcae015. [PMID: 38347944 PMCID: PMC10859637 DOI: 10.1093/braincomms/fcae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/29/2023] [Accepted: 01/19/2024] [Indexed: 02/15/2024] Open
Abstract
Psychosis has often been linked to abnormal cortical asymmetry, but prior results have been inconsistent. Here, we applied a novel spectral shape analysis to characterize cortical shape asymmetries in patients with early psychosis across different spatial scales. We used the Human Connectome Project for Early Psychosis dataset (aged 16-35), comprising 56 healthy controls (37 males, 19 females) and 112 patients with early psychosis (68 males, 44 females). We quantified shape variations of each hemisphere over different spatial frequencies and applied a general linear model to compare differences between healthy controls and patients with early psychosis. We further used canonical correlation analysis to examine associations between shape asymmetries and clinical symptoms. Cortical shape asymmetries, spanning wavelengths from about 22 to 75 mm, were significantly different between healthy controls and patients with early psychosis (Cohen's d = 0.28-0.51), with patients showing greater asymmetry in cortical shape than controls. A single canonical mode linked the asymmetry measures to symptoms (canonical correlation analysis r = 0.45), such that higher cortical asymmetry was correlated with more severe excitement symptoms and less severe emotional distress. Significant group differences in the asymmetries of traditional morphological measures of cortical thickness, surface area, and gyrification, at either global or regional levels, were not identified. Cortical shape asymmetries are more sensitive than other morphological asymmetries in capturing abnormalities in patients with early psychosis. These abnormalities are expressed at coarse spatial scales and are correlated with specific symptom domains.
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Affiliation(s)
- Yu-Chi Chen
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Data Futures Institute, Monash University, Melbourne 3800, Australia
- Brain and Mind Centre, University of Sydney, Sydney 2050, Australia
- Brain Dynamic Centre, Westmead Institute for Medical Research, University of Sydney, Sydney 2145, Australia
| | - Jeggan Tiego
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
| | - Ashlea Segal
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Department of Psychology, Yale University, New Haven, CT 06511, USA
| | - Sidhant Chopra
- Department of Psychology, Yale University, New Haven, CT 06511, USA
| | - Alexander Holmes
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
| | - Chao Suo
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- BrainPark, School of Psychological Sciences, Monash University, Melbourne 3800, Australia
| | - James C Pang
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
| | - Alex Fornito
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
| | - Kevin M Aquino
- School of Psychological Sciences, Turner Institute for Brain and Mental Health, and Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- Monash Biomedical Imaging, Monash University, Melbourne 3800, Australia
- School of Physics, University of Sydney, Sydney 2050, Australia
- Center of Excellence for Integrative Brain Function, University of Sydney, Sydney 2050, Australia
- BrainKey Inc, San Francisco, CA 94103, USA
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Gkantidis N, Opacic J, Kanavakis G, Katsaros C, Halazonetis D. Facial asymmetry and midsagittal plane definition in 3D: A bias-free, automated method. PLoS One 2023; 18:e0294528. [PMID: 38011159 PMCID: PMC10681257 DOI: 10.1371/journal.pone.0294528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/16/2023] [Indexed: 11/29/2023] Open
Abstract
Symmetry is a fundamental biological concept in all living organisms. It is related to a variety of physical and social traits ranging from genetic background integrity and developmental stability to the perception of physical appearance. Within this context, the study of human facial asymmetry carries a unique significance. Here, we validated an efficient method to assess 3D facial surface symmetry by best-fit approximating the original surface to its mirrored one. Following this step, the midsagittal plane of the face was automatically defined at the midpoints of the contralateral corresponding vertices of the superimposed models and colour coded distance maps were constructed. The method was tested by two operators using facial models of different surface size. The results show that the midsagittal plane definition was highly reproducible (maximum error < 0.1 mm or°) and remained robust for different extents of the facial surface model. The symmetry assessments were valid (differences between corresponding bilateral measurement areas < 0.1 mm), highly reproducible (error < 0.01 mm), and were modified by the extent of the initial surface model. The present landmark-free, automated method to assess facial asymmetry and define the midsagittal plane of the face is accurate, objective, easily applicable, comprehensible and cost effective.
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Affiliation(s)
- Nikolaos Gkantidis
- Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Jasmina Opacic
- Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Georgios Kanavakis
- Department of Orthodontics and Pediatric Dentistry, UZB–University School of Dental Medicine, University of Basel, Basel, Switzerland
| | - Christos Katsaros
- Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Demetrios Halazonetis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece
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Jernvall J, Di-Poï N, Mikkola ML, Kratochwil CF. Toward a universal measure of robustness across model organs and systems. Evol Dev 2023; 25:410-417. [PMID: 37070415 DOI: 10.1111/ede.12436] [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: 10/04/2022] [Revised: 04/03/2023] [Accepted: 04/09/2023] [Indexed: 04/19/2023]
Abstract
The development of an individual must be capable of resisting the harmful effects of internal and external perturbations. This capacity, called robustness, can make the difference between normal variation and disease. Some systems and organs are more resilient in their capacity to correct the effects of internal disturbances such as mutations. Similarly, organs and organisms differ in their capacity to be resilient against external disturbances, such as changes in temperature. Furthermore, all developmental systems must be somewhat flexible to permit evolutionary change, and understanding robustness requires a comparative framework. Over the last decades, most research on developmental robustness has been focusing on specific model systems and organs. Hence, we lack tools that would allow cross-species and cross-organ comparisons. Here, we emphasize the need for a uniform framework to experimentally test and quantify robustness across study systems and suggest that the analysis of fluctuating asymmetry might be a powerful proxy to do so. Such a comparative framework will ultimately help to resolve why and how organs of the same and different species differ in their sensitivity to internal (e.g., mutations) and external (e.g., temperature) perturbations and at what level of biological organization buffering capacities exist and therefore create robustness of the developmental system.
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Affiliation(s)
- Jukka Jernvall
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland
| | - Nicolas Di-Poï
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Marja L Mikkola
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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Pavlovič O, Fiala V, Kleisner K. Congruence in European and Asian perception of Vietnamese facial attractiveness, averageness, symmetry and sexual dimorphism. Sci Rep 2023; 13:13320. [PMID: 37587194 PMCID: PMC10432390 DOI: 10.1038/s41598-023-40458-1] [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: 01/20/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Attractiveness is a proposed universal cue to overall biological quality. Nonetheless, local raters and raters of the same ethnicity may be more accurate in assessing the cues for attractiveness than distant and unfamiliar raters. Shared ethnicity and shared environment may both affect rating accuracy: our aim was to compare their relative influence. Therefore, we photographed young Vietnamese participants (N = 93, 33 women) from Hanoi, Vietnam. The photographs were rated by Czechs, Asian Vietnamese, and Czech Vietnamese (raters of Vietnamese origin who lived in Czechia for all or most of their life). Using geometric morphometrics, we measured facial shape cues to biological quality: averageness, asymmetry, and sexual dimorphism. We expected that Vietnamese raters residing in Czechia and Vietnam would agree on perceived attractiveness and use shape-related facial cues to biological quality better than Czech European raters, who are less familiar with East Asians. Surprisingly, mixed-effect models and post hoc comparisons identified no major cross-group differences in attributed attractiveness and path analyses revealed that the three groups based their rating on shape-related characteristics in a similar way. However, despite the considerable cross-cultural agreement regarding perceived attractiveness, Czech European raters associated attractiveness with facial shape averageness significantly more than Vietnamese raters.
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Affiliation(s)
- Ondřej Pavlovič
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Vinicna 7, 128 44, Prague, Czech Republic.
| | - Vojtěch Fiala
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Vinicna 7, 128 44, Prague, Czech Republic
| | - Karel Kleisner
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Vinicna 7, 128 44, Prague, Czech Republic
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Simon B, Mangano FG, Pál A, Simon I, Pellei D, Shahbazi A, Vág J. Palatal asymmetry assessed by intraoral scans: effects of sex, orthodontic treatment, and twinning. A retrospective cohort study. BMC Oral Health 2023; 23:305. [PMID: 37202781 DOI: 10.1186/s12903-023-02993-1] [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: 01/07/2023] [Accepted: 04/27/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Symmetry is critical in perceived attractiveness, especially in female faces. The palate determines the teeth' alignment and supports facial soft tissues. Therefore, the study aimed to assess the effects of sex, orthodontic treatment, age, and heritability on the directional, anti-, and fluctuational asymmetry in the digital palatal model. METHODS The palate of 113 twins, 86 female and 27 male subjects, with and without previous orthodontic treatment, were scanned by the Emerald (Planmeca) intraoral scanner. Three lines were constructed horizontally in the digital model, one between the right and left first upper molars and two between the first molars and incisive papilla. Two observers calculated the left and right angles between the mid-sagittal plane and molar-papilla lines. The intraclass correlation coefficient was used to assess the inter-observer absolute agreement. The directional symmetry was determined by comparing the mean left and right angles. The antisymmetry was estimated from the distribution curve of the signed side difference. The fluctuating asymmetry was approximated from the magnitude of the absolute side difference. Finally, the genetic background was assessed by correlating the absolute side difference between monozygotic twin siblings. RESULTS The right angle (31.1 degrees) was not significantly different from the left one (31.6 degrees). The signed side difference followed a normal distribution with a mean of -0.48 degrees. The absolute side difference (2.29 degrees, p < 0.001) was significantly different from zero and negatively correlated (r=-0.46, p < 0.05) between siblings. None of the asymmetries was affected by sex, orthodontic treatment or age. CONCLUSIONS The palate illustrates neither directional asymmetry nor antisymmetry, indicating that most people's palates are symmetric. However, the significant fluctuating asymmetry suggests that some subject has considerable asymmetry but is not influenced by sex, orthodontic treatment, age, and genetics. The proposed digital method is a reliable and non-invasive tool that could facilitate achieving a more symmetrical structure during orthodontic and aesthetic rehabilitation. TRIAL REGISTRATION The Clinicatrial.gov registration number is NCT05349942 (27/04/2022).
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Affiliation(s)
- Botond Simon
- Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary.
| | - Francesco Guido Mangano
- Department of Pediatric, Preventive Dentistry and Orthodontics, Sechenov First State Medical University, Moscow, Russia
| | - Adrienn Pál
- Department of Prosthodontics, Semmelweis University, Budapest, Hungary
| | - István Simon
- Department of Paediatric Dentistry and Orthodontics, Semmelweis University, Budapest, Hungary
| | - Dalma Pellei
- Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary
| | - Arvin Shahbazi
- Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary
- Department of Anatomy, Histology and Embryology (Oral Morphology Group), Semmelweis University, Budapest, Hungary
- Department of Periodontology, Semmelweis University, Budapest, Hungary
| | - János Vág
- Department of Restorative Dentistry and Endodontics, Semmelweis University, Budapest, Hungary
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Ertuğrul B, Aydık MF. No association between developmental instability as a general measure of stress and 2D:4D digit ratios in a non-western sample. Am J Hum Biol 2023; 35:e23860. [PMID: 36602102 DOI: 10.1002/ajhb.23860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Random deviation from perfect symmetry of organisms is defined as fluctuating asymmetry. Fluctuating asymmetry is widely considered to be a marker of developmental instability, developmental noise and phenotypic quality at the population level. In this study, we investigated hypothesized relationship between 2D:4D digit ratios as a proxy measure of prenatal sex hormones and developmental instability levels in young adult humans. MATERIALS AND METHODS In the study, seven bilateral traits were measured for fluctuating asymmetry, as well as second and fourth digit lengths on both hands of 185 individuals, 87 men (mean age: 22.42 ± 3.37) and 97 women (mean age: 22.88 ± 3.87). The second digit length was divided by the fourth digit length and the resulting value was used as the digit ratio (2D:4D). Composite fluctuating asymmetry was calculated using five bilateral traits displaying fluctuating asymmetry. RESULTS Only the right hand 2D:4D ratio is lower in men than in women. However, this difference disappears when the effect of digit lengths is controlled. Composite fluctuating asymmetry results reveal that men are more asymmetrical than women. There was no significant relationship between digit ratios and composite fluctuating asymmetry. CONCLUSION In this study, the 2D:4D digit ratios appear to be influenced (at least in humans) by different digit lengths. This study also confirms previous studies that digit ratios as a proxy measure of exposure to either high testosterone or estrogen levels during early development does not appear to affect levels of developmental instability.
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Affiliation(s)
- Berna Ertuğrul
- Faculty of Literature, Department of Anthropology, İstanbul University, İstanbul, Turkey
| | - Muhammet Fatih Aydık
- Faculty of Literature, Department of Anthropology, İstanbul University, İstanbul, Turkey
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Liu E, Wing D. Population effects of chiral snail shell development relate handedness to health and disease. JOURNAL OF UNDERGRADUATE LIFE SCIENCES 2022. [DOI: 10.33137/juls.v16i1.39954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The spiral patterns of snail shells exhibit chirality, or “handedness.” These patterns often heavily favor the dextral (right-handed, or clockwise) over the sinistral (left-handed, clockwise) phenotype. While the developmental pathways resulting in each enantiomorph (non-superimposable mirror image form) have been studied extensively, there has been limited investigation into how the emphasis on one spiral direction over the other may confer survival benefit. This perspective essay proposes that developmental events determining cell cleavage robustness, mating compatibility, and predator evasion can influence the distribution of dextral and sinistral snails. The connection between chirality and survivability has broader implications for exploring the role of handedness in diseases and their treatments.
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Farrera A. Formal models for the study of the relationship between fluctuating asymmetry and fitness in humans. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 179:73-84. [PMID: 36790746 PMCID: PMC9540978 DOI: 10.1002/ajpa.24588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/04/2022] [Accepted: 06/20/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVES To evaluate three of the main verbal models that have been proposed to explain the relationship between fluctuating asymmetry and fitness in humans: the "good genes," the "good development," and the "growth" hypotheses. MATERIALS AND METHODS A formal model was generated for each verbal model following three steps. First, based on the literature, a theoretical causal model and the theoretical object of inquiry were outlined. Second, an empirical causal model and the targets of inference were defined using observational data of facial asymmetries and life-history traits related to fitness. Third, generalized linear models and causal inference were used as the estimation strategy. RESULTS The results suggest that the theoretical and empirical assumptions of the "good genes" hypothesis should be reformulated. The results were compatible with most of the empirical assumptions of "the good development" hypothesis but suggest that further discussion of its theoretical assumptions is needed. The results were less informative about the "growth" hypothesis, both theoretically and empirically. There was a positive association between facial fluctuating asymmetry and the number of offspring that was not compatible with any of the empirical causal models evaluated. CONCLUSIONS Although the three hypotheses focus on different aspects of the link between asymmetry and fitness, their overlap opens the possibility of a unified theory on the subject. The results of this study make explicit which assumptions need to be updated and discussed, facilitating the advancement of this area of research. Overall, this study elucidates the potential benefit of using formal models for theory revision and development.
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Affiliation(s)
- Arodi Farrera
- Mathematical Modeling of Social Systems DepartmentInstitute for Research on Applied Mathematics and Systems, National Autonomous University of MexicoMexico CityMexico
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12
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Developmental instability, fluctuating asymmetry, and human psychological science. Emerg Top Life Sci 2022; 6:311-322. [PMID: 35994000 DOI: 10.1042/etls20220025] [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: 03/11/2022] [Revised: 06/22/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022]
Abstract
Developmental instability (DI) is an individual's inability to produce a specific developmental outcome under a given set of conditions, generally thought to result from random perturbations experienced during development. Fluctuating asymmetry (FA) - asymmetry on bilateral features that, on average, are symmetrical (or asymmetry deviating from that arising from design) - has been used to measure DI. Dating to half a century ago, and accelerating in the past three decades, psychological researchers have examined associations between FA (typically measured on bodily or facial features) and a host of outcomes of interest, including psychological disorders, cognitive ability, attractiveness, and sexual behavior. A decade ago, a meta-analysis on findings from nearly 100 studies extracted several conclusions. On average, small but statistically reliable associations between FA and traits of interest exist. Though modest, these associations are expected to greatly underestimate the strength of associations with underlying DI. Despite the massive sample size across studies, we still lack a good handle on which traits are most strongly affected by DI. A major methodological implication of the meta-analysis is that most studies have been, individually, woefully underpowered to detect associations. Though offering some intriguing findings, much research is the past decade too has been underpowered; hence, the newer literature is also likely noisy. Several large-scale studies are exceptions. Future progress depends on additional large-scale studies and researchers' sensitivity to power issues. As well, theoretical assumptions and conceptualizations of DI and FA driving psychological research may need revision to explain empirical patterns.
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Anthropometric fluctuating asymmetries in living humans through the eyes of an anthropologist. Emerg Top Life Sci 2022; 6:323-331. [PMID: 35916213 DOI: 10.1042/etls20210276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022]
Abstract
There are many environmental and genetic factors that disrupt the stable structure of development in organisms. Although the strength of these vary, they leave certain signs in the body structure. Fluctuating asymmetry is a widely used population-level index of developmental instability, developmental noise, and robustness. Many bilateral traits are used in fluctuating asymmetry studies in humans. These traits include dermatoglyphics, limb lengths and widths, bilateral facial characters, and teeth. In this review, I evaluate the measurement methods of many bilateral anthropometric characters, taken from the bodies of living individuals with classical digital calipers.
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Mitteroecker P, Schaefer K. Thirty years of geometric morphometrics: Achievements, challenges, and the ongoing quest for biological meaningfulness. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 178 Suppl 74:181-210. [PMID: 36790612 PMCID: PMC9545184 DOI: 10.1002/ajpa.24531] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/28/2022] [Accepted: 04/17/2022] [Indexed: 12/30/2022]
Abstract
The foundations of geometric morphometrics were worked out about 30 years ago and have continually been refined and extended. What has remained as a central thrust and source of debate in the morphometrics community is the shared goal of meaningful biological inference through a tight connection between biological theory, measurement, multivariate biostatistics, and geometry. Here we review the building blocks of modern geometric morphometrics: the representation of organismal geometry by landmarks and semilandmarks, the computation of shape or form variables via superimposition, the visualization of statistical results as actual shapes or forms, the decomposition of shape variation into symmetric and asymmetric components and into different spatial scales, the interpretation of various geometries in shape or form space, and models of the association between shape or form and other variables, such as environmental, genetic, or behavioral data. We focus on recent developments and current methodological challenges, especially those arising from the increasing number of landmarks and semilandmarks, and emphasize the importance of thorough exploratory multivariate analyses rather than single scalar summary statistics. We outline promising directions for further research and for the evaluation of new developments, such as "landmark-free" approaches. To illustrate these methods, we analyze three-dimensional human face shape based on data from the Avon Longitudinal Study of Parents and Children (ALSPAC).
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Affiliation(s)
- Philipp Mitteroecker
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
| | - Katrin Schaefer
- Department of Evolutionary AnthropologyUniversity of ViennaViennaAustria,Human Evolution and Archaeological Sciences (HEAS)University of ViennaViennaAustria
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15
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Symmetry and Asymmetry of the Antegonial Notch. Symmetry (Basel) 2022. [DOI: 10.3390/sym14081558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The symmetry of a human organism’s structure is an expression of the general law of development regarding organic life. Assessing the symmetry of the face and its individual components is one of the most important factors when it comes to the overall assessment of a patient’s stomatognathic system and is essential in the planning of orthodontic and prosthetic treatment. The aim of this study is to assess the symmetry of the occurrence and the measurement parameters of the pre-angular notch of the mandible. The study included computed tomography scans of 187 patients who all exhibited a visible pre-angular notch in the mandible. There was a noticeable and measurable asymmetry in the length of the angle of the notches as well as in the area of the notch angles. The differentiation of the right- and left-side measurements points to the existence of a fluctuating asymmetry. Other measurements which describe the pre-angular notch of the lower jaw do not show asymmetry.
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16
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The biological significance of tooth identification based on developmental and evolutional viewpoints. J Oral Biosci 2022; 64:287-302. [DOI: 10.1016/j.job.2022.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 11/22/2022]
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17
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Cerebral Polymorphisms for Lateralisation: Modelling the Genetic and Phenotypic Architectures of Multiple Functional Modules. Symmetry (Basel) 2022. [DOI: 10.3390/sym14040814] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, and visuo-spatial functioning, while typically left, left and right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers of modules and participants are finding increasing numbers of module combinations, which here are termed cerebral polymorphisms—qualitatively different lateral organisations of cognitive functions. Polymorphisms are more frequent in left-handers than right-handers, but it is far from the case that right-handers all show the lateral organisation of modules described in introductory textbooks. In computational terms, this paper extends the original, monogenic McManus DC (dextral-chance) model of handedness and language dominance to multiple functional modules, and to a polygenic DC model compatible with the molecular genetics of handedness, and with the biology of visceral asymmetries found in primary ciliary dyskinesia. Distributions of cerebral polymorphisms are calculated for families and twins, and consequences and implications of cerebral polymorphisms are explored for explaining aphasia due to cerebral damage, as well as possible talents and deficits arising from atypical inter- and intra-hemispheric modular connections. The model is set in the broader context of the testing of psychological theories, of issues of laterality measurement, of mutation-selection balance, and the evolution of brain and visceral asymmetries.
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18
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Abstract
The human voice carries socially relevant information such as how authoritative, dominant, and attractive the speaker sounds. However, some speakers may be able to manipulate listeners by modulating the shape and size of their vocal tract to exaggerate certain characteristics of their voice. We analysed the veridical size of speakers’ vocal tracts using real-time magnetic resonance imaging as they volitionally modulated their voice to sound larger or smaller, corresponding changes to the size implied by the acoustics of their voice, and their influence over the perceptions of listeners. Individual differences in this ability were marked, spanning from nearly incapable to nearly perfect vocal modulation, and was consistent across modalities of measurement. Further research is needed to determine whether speakers who are effective at vocal size exaggeration are better able to manipulate their social environment, and whether this variation is an inherited quality of the individual, or the result of life experiences such as vocal training.
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19
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Chen YC, Arnatkevičiūtė A, McTavish E, Pang JC, Chopra S, Suo C, Fornito A, Aquino KM. The individuality of shape asymmetries of the human cerebral cortex. eLife 2022; 11:75056. [PMID: 36197720 PMCID: PMC9668337 DOI: 10.7554/elife.75056] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 10/04/2022] [Indexed: 01/05/2023] Open
Abstract
Asymmetries of the cerebral cortex are found across diverse phyla and are particularly pronounced in humans, with important implications for brain function and disease. However, many prior studies have confounded asymmetries due to size with those due to shape. Here, we introduce a novel approach to characterize asymmetries of the whole cortical shape, independent of size, across different spatial frequencies using magnetic resonance imaging data in three independent datasets. We find that cortical shape asymmetry is highly individualized and robust, akin to a cortical fingerprint, and identifies individuals more accurately than size-based descriptors, such as cortical thickness and surface area, or measures of inter-regional functional coupling of brain activity. Individual identifiability is optimal at coarse spatial scales (~37 mm wavelength), and shape asymmetries show scale-specific associations with sex and cognition, but not handedness. While unihemispheric cortical shape shows significant heritability at coarse scales (~65 mm wavelength), shape asymmetries are determined primarily by subject-specific environmental effects. Thus, coarse-scale shape asymmetries are highly personalized, sexually dimorphic, linked to individual differences in cognition, and are primarily driven by stochastic environmental influences.
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Affiliation(s)
- Yu-Chi Chen
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia,Monash Data Futures Institute, Monash UniversityMelbourneAustralia
| | - Aurina Arnatkevičiūtė
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia
| | - Eugene McTavish
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia,Healthy Brain and Mind Research Centre, Faculty of Health Sciences, Australian Catholic UniversityFitzroyAustralia
| | - James C Pang
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia
| | - Sidhant Chopra
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia,Department of Psychology, Yale UniversityNew HavenUnited States
| | - Chao Suo
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia,BrainPark, Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia
| | - Alex Fornito
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia
| | - Kevin M Aquino
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash UniversityMelbourneAustralia,Monash Biomedical Imaging, Monash UniversityMelbourneAustralia,School of Physics, University of SydneySydneyAustralia,Center of Excellence for Integrative Brain Function, University of SydneySydneyAustralia,BrainKey IncSan FranciscoUnited States
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20
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González‐Ruiz JM, Pérez‐Núñez MI, García‐Alfaro MD, Bastir M. How can directional and fluctuating asymmetry help in the prognosis of scoliosis along the course of the condition? J Anat 2021; 239:1400-1408. [PMID: 34263453 PMCID: PMC8602023 DOI: 10.1111/joa.13509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/21/2022] Open
Abstract
Fluctuating asymmetry (FA) is an indicator of developmental instability referred to random deviations from mean asymmetry. That average asymmetry is the directional asymmetry (DA), which, in the particular case of adolescent idiopathic scoliosis (AIS), corresponds to a right thoracic and left lumbar curves. Investigating the presence of FA and DA in AIS has never been done, and it is a key element of the pathophysiology of the scoliotic condition. Thirty-six X-rays of patients with AIS were digitized and analysed using Geometric Morphometric analyses to test for both statistical effects. The individual FA score for each patient was calculated using Procrustes ANOVA and a methodology based on the components of shape was used to estimate the individual DA score. DA is a stronger effect than FA (2.12 to 1), as it has been found in other clinical conditions. The individual DA score, with an effect size of 0.58, is a better predictor of the Cobb angle than FA score. The methodology presented in this paper to estimate DA score is a valid approach in the study of asymmetries in AIS. FA should be correlated in future studies with environmental covariates to serve as a variable in the medical prognosis, while DA will serve as a good predictor of the Cobb angle during the course of the condition, avoiding the abuse of X-rays. This potential use of DA should be tested on 3D shape due to the three-dimensional clinical presentation of AIS.
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Affiliation(s)
- José María González‐Ruiz
- Virtual Morphology LabMuseo Nacional de Ciencias Naturales – Consejo Superior de Investigaciones CientíficasMadridSpain
| | - María Isabel Pérez‐Núñez
- Department of Orthopedic Surgery and TraumatologyUniversity Hospital of ValdecillaUniversity of CantabriaSantanderSpain
| | - Mª Dolores García‐Alfaro
- Department of Orthopedic Surgery and TraumatologyUniversity Hospital of ValdecillaUniversity of CantabriaSantanderSpain
| | - Markus Bastir
- Virtual Morphology LabMuseo Nacional de Ciencias Naturales – Consejo Superior de Investigaciones CientíficasMadridSpain
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21
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Hou M, Fagan MJ. Assessments of bilateral asymmetry with application in human skull analysis. PLoS One 2021; 16:e0258146. [PMID: 34614014 PMCID: PMC8494363 DOI: 10.1371/journal.pone.0258146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/21/2021] [Indexed: 11/19/2022] Open
Abstract
As a common feature, bilateral symmetry of biological forms is ubiquitous, but in fact rarely exact. In a setting of analytic geometry, bilateral symmetry is defined with respect to a point, line or plane, and the well-known notions of fluctuating asymmetry, directional asymmetry and antisymmetry are recast. A meticulous scheme for asymmetry assessments is proposed and explicit solutions to them are derived. An investigation into observational errors of points representing the geometric structure of an object offers a baseline reference for asymmetry assessment of the object. The proposed assessments are applicable to individual, part or all point pairs at both individual and collective levels. The exact relationship between the developed treatments and the widely used Procrustes method in asymmetry assessment is examined. An application of the proposed assessments to a large collection of human skull data in the form of 3D landmark coordinates finds: (a) asymmetry of most skulls is not fluctuating, but directional if measured about a plane fitted to shared landmarks or side landmarks for balancing; (b) asymmetry becomes completely fluctuating if one side of a skull could be slightly rotated and translated with respect to the other side; (c) female skulls are more asymmetric than male skulls. The methodology developed in this study is rigorous and transparent, and lays an analytical base for investigation of structural symmetries and asymmetries in a wide range of biological and medical applications.
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Affiliation(s)
- M. Hou
- Department of Engineering, Medical and Biological Engineering, Faculty of Science & Engineering, University of Hull, Hull, United Kingdom
| | - M. J. Fagan
- Department of Engineering, Medical and Biological Engineering, Faculty of Science & Engineering, University of Hull, Hull, United Kingdom
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22
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Tan DW, Gilani SZ, Boutrus M, Alvares GA, Whitehouse AJO, Mian A, Suter D, Maybery MT. Facial asymmetry in parents of children on the autism spectrum. Autism Res 2021; 14:2260-2269. [PMID: 34529361 DOI: 10.1002/aur.2612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/05/2021] [Accepted: 08/25/2021] [Indexed: 11/08/2022]
Abstract
Greater facial asymmetry has been consistently found in children with autism spectrum disorder (ASD) relative to children without ASD. There is substantial evidence that both facial structure and the recurrence of ASD diagnosis are highly heritable within a nuclear family. Furthermore, sub-clinical levels of autistic-like behavioural characteristics have also been reported in first-degree relatives of individuals with ASD, commonly known as the 'broad autism phenotype'. Therefore, the aim of the current study was to examine whether a broad autism phenotype expresses as facial asymmetry among 192 biological parents of autistic individuals (134 mothers) compared to those of 163 age-matched adults without a family history of ASD (113 females). Using dense surface-modelling techniques on three dimensional facial images, we found evidence for greater facial asymmetry in parents of autistic individuals compared to age-matched adults in the comparison group (p = 0.046, d = 0.21 [0.002, 0.42]). Considering previous findings and the current results, we conclude that facial asymmetry expressed in the facial morphology of autistic children may be related to heritability factors. LAY ABSTRACT: In a previous study, we showed that autistic children presented with greater facial asymmetry than non-autistic children. In the current study, we examined the amount of facial asymmetry shown on three-dimensional facial images of 192 parents of autistic children compared to a control group consisting of 163 similarly aged adults with no known history of autism. Although parents did show greater levels of facial asymmetry than those in the control group, this effect is statistically small. We concluded that the facial asymmetry previously found in autistic children may be related to genetic factors.
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Affiliation(s)
- Diana Weiting Tan
- School of Psychological Science, The University of Western Australia, Perth, Western Australia, Australia.,Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Syed Zulqarnain Gilani
- School of Sciences, Edith Cowan University, Perth, Western Australia, Australia.,School of Computer Science and Software Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - Maryam Boutrus
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Gail A Alvares
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Andrew J O Whitehouse
- Telethon Kids Institute, The University of Western Australia, Perth, Western Australia, Australia
| | - Ajmal Mian
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Western Australia, Australia
| | - David Suter
- School of Sciences, Edith Cowan University, Perth, Western Australia, Australia
| | - Murray T Maybery
- School of Psychological Science, The University of Western Australia, Perth, Western Australia, Australia
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23
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Assessment of the Orbital and Auricular Asymmetry in Italian and Sudanese Children: A Three-Dimensional Study. Symmetry (Basel) 2021. [DOI: 10.3390/sym13091657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The evaluation of the symmetry of orbital and ear soft tissues is important for aesthetic and reconstructive surgery. However, little information is available for these facial regions, especially in children. We analyzed the orbital and auricular symmetry in 418 Italian and 206 Sudanese subadult males divided into three age groups (8–11, 12–15, and 16–19 years old). Orbital and auricular height and width were measured for calculating fluctuating and directional asymmetry indices. Differences in asymmetry indices according to ethnicity and age group were assessed through the two-way ANOVA test (p < 0.01), while differences in the prevalence of right or left asymmetry according to ethnicity were assessed through the chi-square test. On average, directional asymmetry indices ranged from −2.1% to 1.1%, while fluctuating asymmetry indices ranged between 2.9% and 5.4%, corresponding to a small effect size and to 1.06–2.34 mm actual dimensions. Sudanese subjects showed a greater asymmetry for all the indices except for the fluctuating asymmetry of orbital height (p < 0.01). The directional asymmetry of auricular width increased with age. A prevalent right-side asymmetry was found for all the orbital indices (p < 0.001) in both populations, although significantly more prevalent in Sudanese individuals (over 83% for both measures), while auricular measures showed a prevalent left asymmetry exclusively in the Sudanese but with lower percentages. Aside from the limited effect size, the results proved the ethnic variability of asymmetry of orbital and auricle regions in children and suggest the need to collect more population data.
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24
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A New Integrated Tool to Calculate and Map Bilateral Asymmetry on Three-Dimensional Digital Models. Symmetry (Basel) 2021. [DOI: 10.3390/sym13091644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The observation and the quantification of asymmetry in biological structures are deeply investigated in geometric morphometrics. Patterns of asymmetry were explored in both living and fossil species. In living organisms, levels of directional and fluctuating asymmetry are informative about developmental processes and health status of the individuals. Paleontologists are primarily interested in asymmetric features introduced by the taphonomic process, as they may significantly alter the original shape of the biological remains, hampering the interpretation of morphological features which may have profound evolutionary significance. Here, we provide a new R tool that produces the numerical quantification of fluctuating and directional asymmetry and charts asymmetry directly on the specimens under study, allowing the visual inspection of the asymmetry pattern. We tested this show.asymmetry algorithm, written in the R language, on fossil and living cranial remains of the genus Homo. show.asymmetry proved successful in discriminating levels of asymmetry among sexes in Homo sapiens, to tell apart fossil from living Homo skulls, to map effectively taphonomic distortion directly on the fossil skulls, and to provide evidence that digital restoration obliterates natural asymmetry to unnaturally low levels.
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25
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Sajid M, Ali N, Ratyal NI, Dar SH, Zafar B. Facial asymmetry-based feature extraction for different applications: a review complemented by new advances. Artif Intell Rev 2021. [DOI: 10.1007/s10462-021-10001-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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26
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Abstract
BACKGROUND Developmental instability is a component of non-genetic variation that results from random variation in developmental processes. It is considered a sensitive indicator of the physiological state of individuals. It is reflected in various ways, but in this study we focussed on its reflection in fluctuating asymmetry (FA) and morphological integration. AIM To assess how, if at all, variations of facial morphology mirror developmental instability across childhood with respect to sex, growth rate and socioeconomic/environmental factors. SUBJECTS AND METHODS A set of 210 three-dimensional facial models (of children aged between 6.3 and 14.3 years) originating from the FIDENTIS 3D Face Database was subjected to landmark-based methods of geometric morphometrics to quantify the degree of facial asymmetry and facial morphological integration. In addition, the association with age, sex, and socioeconomic factors was assessed. RESULTS Our results showed a nonlinear increase of FA with age up to the age of 14 years. The pattern of sex-related variants in facial FA differed in relation to age, as girls exhibited higher values of FA than boys up to the age of 9 years. We found that a signal of modularity based on functional demands and organisation of the face is of particular importance. Here, girls exhibited higher morphological covariation among modules. During more rapid adolescence-related growth, however, covariation among modules at the asymmetrical level decreased in both sexes. CONCLUSION We can conclude that facial morphology was shown to be strongly integrated, particularly until adolescence. This covariation can facilitate an increase of FA. In addition, the results of this study indicate there is a weak association between socioeconomic stress and facial asymmetries. In contrast, sex and growth rate are reflected in developmental instability.
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Affiliation(s)
- Marie Jandová
- Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Petra Urbanová
- Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
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27
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Nature, Nurture, and Noise: Developmental Instability, Fluctuating Asymmetry, and the Causes of Phenotypic Variation. Symmetry (Basel) 2021. [DOI: 10.3390/sym13071204] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Phenotypic variation arises from genetic and environmental variation, as well as random aspects of development. The genetic (nature) and environmental (nurture) components of this variation have been appreciated since at least 1900. The random developmental component (noise) has taken longer for quantitative geneticists to appreciate. Here, I sketch the historical development of the concepts of random developmental noise and developmental instability, and its quantification via fluctuating asymmetry. The unsung pioneers in this story are Hugo DeVries (fluctuating variation, 1909), C. H. Danforth (random variation between monozygotic twins, 1919), and Sewall Wright (random developmental variation in piebald guinea pigs, 1920). The first pioneering study of fluctuating asymmetry, by Sumner and Huestis in 1921, is seldom mentioned, possibly because it failed to connect the observed random asymmetry with random developmental variation. This early work was then synthesized by Boris Astaurov in 1930 and Wilhelm Ludwig in 1932, and then popularized by Drosophila geneticists beginning with Kenneth Mather in 1953. Population phenogeneticists are still trying to understand the origins and behavior of random developmental variation. Some of the developmental noise represents true stochastic behavior of molecules and cells, while some represents deterministic chaos, nonlinear feedback, and symmetry breaking.
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28
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Boutrus M, Gilani Z, Maybery MT, Alvares GA, Tan DW, Eastwood PR, Mian A, Whitehouse AJO. Brief Report: Facial Asymmetry and Autistic-Like Traits in the General Population. J Autism Dev Disord 2021; 51:2115-2123. [PMID: 32844273 DOI: 10.1007/s10803-020-04661-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Atypical facial morphology, particularly increased facial asymmetry, has been identified in some individuals with Autism Spectrum Conditions (ASC). Many cognitive, behavioural and biological features associated with ASC also occur on a continuum in the general population. The aim of the present study was to examine subthreshold levels of autistic traits and facial morphology in non-autistic individuals. Facial asymmetry was measured using three-dimensional facial photogrammetry, and the Autism-spectrum Quotient was used to measure autistic-like traits in a community-ascertained sample of young adults (n = 289). After accounting for covariates, there were no significant associations observed between autistic-like traits and facial asymmetry, suggesting that any potential facial morphology differences linked to ASC may be limited to the clinical condition.
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Affiliation(s)
- Maryam Boutrus
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia. .,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia. .,School of Psychological Science, University of Western Australia, Perth, Australia.
| | - Zulqarnain Gilani
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia.,School of Science, Edith Cowan University, Perth, Australia
| | - Murray T Maybery
- School of Psychological Science, University of Western Australia, Perth, Australia
| | - Gail A Alvares
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
| | - Diana W Tan
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,School of Psychological Science, University of Western Australia, Perth, Australia
| | - Peter R Eastwood
- School of Human Sciences, Centre for Sleep Science, University of Western Australia, Perth, Australia.,Department of Pulmonary Physiology & Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth,, Australia
| | - Ajmal Mian
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia
| | - Andrew J O Whitehouse
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
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29
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Neustupa J, Woodard K. Male sterility significantly elevates shape variation and fluctuating asymmetry of zygomorphic corolla in gynodioecious Glechoma hederacea (Lamiaceae). AOB PLANTS 2021; 13:plab013. [PMID: 33981404 PMCID: PMC8102666 DOI: 10.1093/aobpla/plab013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Female flowers of gynodioecious plants usually have smaller corollas than bisexual flowers. This difference is explained as a developmental consequence of stamen abortion and as a result of stronger selection for larger corolla size in hermaphroditic flowers that solely ensure male function within populations. This study evaluated whether the size difference of zygomorphic corollas in a widely distributed gynodioecious herb Glechoma hederacea is accompanied by variation in shape and bilateral fluctuating asymmetry of sexually differentiated flowers. Geometric morphometric analyses of bilateral symmetry in the shapes of corolla lower lips showed that male-sterile flowers were significantly more plastic and asymmetric, implying that they may be subjected to weaker stabilizing selection for corolla shape in comparison to hermaphrodites. These results illustrated that sexual differentiation may be an important factor contributing to bilateral fluctuating asymmetry in the shape of zygomorphic flowers.
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Affiliation(s)
- Jiri Neustupa
- Department of Botany, Faculty of Science, Charles University, Prague 12843, Czech Republic
| | - Katerina Woodard
- Department of Botany, Faculty of Science, Charles University, Prague 12843, Czech Republic
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30
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Zheng R, Ren D, Xie C, Pan J, Zhou G. Normality mediates the effect of symmetry on facial attractiveness. Acta Psychol (Amst) 2021; 217:103311. [PMID: 33933836 DOI: 10.1016/j.actpsy.2021.103311] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 11/18/2022] Open
Abstract
Although symmetry, averageness, and sexual dimorphism are usually considered important to facial attractiveness, there are mixed findings regarding whether and how symmetry influences facial attractiveness. The present study introduced "facial normality" to explain the inconsistency of previous research. We hypothesized that symmetry only increased facial attractiveness when it improved facial normality. We manipulated symmetry and normality simultaneously on sixteen Chinese male faces and asked participants to rate the perceived symmetry, perceived normality, and facial attractiveness. The results demonstrated an interactive effect of symmetry and normality on facial attractiveness. The structural equation model results showed two paths from symmetry to facial attractiveness: (1) Symmetry reduced facial attractiveness by decreasing perceived normality; (2) Symmetry increased facial attractiveness by increasing the perceived symmetry and then improving perceived normality. In other words, perceived normality acted as a mediator between symmetry and facial attractiveness. The present study provides a solution to the different effects of symmetry on facial attractiveness in previous studies and suggests that future studies on symmetry and facial attractiveness should consider the mediating role of normality.
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Affiliation(s)
- Ruoying Zheng
- Department of Psychology, Sun Yat-sen University, Guangzhou, China
| | - Dongyan Ren
- Department of Psychology, Sun Yat-sen University, Guangzhou, China
| | - Chunyan Xie
- Department of Psychology, Sun Yat-sen University, Guangzhou, China
| | - Junhao Pan
- Department of Psychology, Sun Yat-sen University, Guangzhou, China
| | - Guomei Zhou
- Department of Psychology, Sun Yat-sen University, Guangzhou, China.
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Luoto S, Krama T, Rubika A, Borráz-León JI, Trakimas G, Elferts D, Skrinda I, Krams R, Moore FR, Birbele E, Kaminska I, Contreras-Garduño J, Rantala MJ, Krams IA. Socioeconomic position, immune function, and its physiological markers. Psychoneuroendocrinology 2021; 127:105202. [PMID: 33756285 DOI: 10.1016/j.psyneuen.2021.105202] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/23/2021] [Accepted: 03/12/2021] [Indexed: 02/07/2023]
Abstract
The development of costly traits such as immune function and secondary sexual traits is constrained by resource availability. The quality of developmental conditions and the availability of resources in ontogeny may therefore influence immune system functions and other biological traits. We analyzed causal pathways between family socioeconomic position, strength of immune response, and five physiological biomarkers in young Latvian men (n = 93) using structural equation modeling. Men from wealthier families had higher testosterone levels (rs = 0.280), stronger immune response (rs = 0.551), and higher facial attractiveness (rs = 0.300). There were weak, non-significant correlations between family income, body fat percentage (rs = -0.147), and fluctuating asymmetry (rs = -0.159). Testosterone partially (33.8%) mediated the effect of family income on facial masculinity. Testosterone (positively) and adiposity (negatively) partially (4%) mediated the relationship between family income and immune function. Higher facial masculinity, higher facial symmetry, and lower adiposity were reliable and independent cues of better immune function (R2 = 0.238) in a larger sample of young Latvian men (N = 146). Resource availability in ontogeny has an important role for the development of immune function and physical appearance, and it is a key parameter to be included in human eco-immunological research.
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Affiliation(s)
- Severi Luoto
- School of Psychology, University of Auckland, Auckland, New Zealand
| | - Tatjana Krama
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia; Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia; Department of Biotechnology, Daugavpils University, Daugavpils, Latvia
| | - Anna Rubika
- Department of Anatomy and Physiology, Daugavpils University, Daugavpils, Latvia
| | - Javier I Borráz-León
- Department of Biology, University of Turku, Turku, Finland; Department of Ethology, National Institute of Psychiatry "Ramón de la Fuente Muñiz", Mexico City, Mexico
| | - Giedrius Trakimas
- Institute of Biosciences, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Didzis Elferts
- Department of Botany and Ecology, Faculty of Biology, University of Latvia, Rīga, Latvia
| | | | - Ronalds Krams
- Chair of Plant Health, Estonian University of Life Sciences, Tartu, Estonia; Department of Biotechnology, Daugavpils University, Daugavpils, Latvia; Department of Anatomy and Physiology, Daugavpils University, Daugavpils, Latvia
| | - Fhionna R Moore
- Institute of Health and Wellbeing, University of Glasgow, United Kingdom
| | - Elza Birbele
- Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Rīga, Latvia
| | - Irena Kaminska
- Department of Anatomy and Physiology, Daugavpils University, Daugavpils, Latvia
| | - Jorge Contreras-Garduño
- Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México, Morelia, Mexico
| | - Markus J Rantala
- Department of Biology & Turku Brain and Mind Centre, University of Turku, Turku, Finland
| | - Indrikis A Krams
- Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia; Department of Biotechnology, Daugavpils University, Daugavpils, Latvia; Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Rīga, Latvia.
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Balestrini S, Lopez SM, Chinthapalli K, Sargsyan N, Demurtas R, Vos S, Altmann A, Suttie M, Hammond P, Sisodiya SM. Increased facial asymmetry in focal epilepsies associated with unilateral lesions. Brain Commun 2021; 3:fcab068. [PMID: 34222868 PMCID: PMC8244637 DOI: 10.1093/braincomms/fcab068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/20/2021] [Accepted: 03/11/2021] [Indexed: 12/22/2022] Open
Abstract
The epilepsies are now conceptualized as network disruptions: focal epilepsies are considered to have network alterations in the hemisphere of seizure onset, whilst generalized epilepsies are considered to have bi-hemispheric network changes. Increasingly, many epilepsies are also considered to be neurodevelopmental disorders, with early changes in the brain underpinning seizure biology. The development of the structure of the face is influenced by complex molecular interactions between surface ectoderm and underlying developing forebrain and neural crest cells. This influence is likely to continue postnatally, given the evidence of facial growth changes over time in humans until at least 18 years of age. In this case-control study, we hypothesized that people with lateralized focal epilepsies (i.e. unilateral network changes) have an increased degree of facial asymmetry, compared with people with generalized epilepsies or controls without epilepsy. We applied three-dimensional stereophotogrammetry and dense surface models to evaluate facial asymmetry in people with epilepsy, aiming to generate new tools to explore pathophysiological mechanisms in epilepsy. We analysed neuroimaging data to explore the correlation between face and brain asymmetry. We consecutively recruited 859 people with epilepsy attending the epilepsy clinics at a tertiary referral centre. We used dense surface modelling of the full face and signature analyses of three-dimensional facial photographs to analyse facial differences between 378 cases and 205 healthy controls. Neuroimaging around the time of the facial photograph was available for 234 cases. We computed the brain asymmetry index between contralateral regions. Cases with focal symptomatic epilepsy associated with unilateral lesions showed greater facial asymmetry compared to controls (P = 0.0001, two-sample t-test). This finding was confirmed by linear regression analysis after controlling for age and gender. We also found a significant correlation between duration of illness and the brain asymmetry index of total average cortical thickness (r = -0.19, P = 0.0075) but not for total average surface area (r = 0.06, P = 0.3968). There was no significant correlation between facial asymmetry and asymmetry of regional cortical thickness or surface area. We propose that the greater facial asymmetry in cases with focal epilepsy caused by unilateral abnormality might be explained by early unilateral network disruption, and that this is independent of underlying brain asymmetry. Three-dimensional stereophotogrammetry and dense surface modelling are a novel powerful phenotyping tool in epilepsy that may permit greater understanding of pathophysiology in epilepsy, and generate further insights into the development of cerebral networks underlying epilepsy, and the genetics of facial and neural development.
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Affiliation(s)
- Simona Balestrini
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London.,Chalfont Centre for Epilepsy, Gerrards Cross, UK
| | - Seymour M Lopez
- Department of Medical Physics, Centre for Medical Image Computing, UCL, London, UK
| | - Krishna Chinthapalli
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London.,Chalfont Centre for Epilepsy, Gerrards Cross, UK
| | - Narek Sargsyan
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London.,Chalfont Centre for Epilepsy, Gerrards Cross, UK
| | - Rita Demurtas
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London.,Chalfont Centre for Epilepsy, Gerrards Cross, UK
| | - Sjoerd Vos
- Department of Medical Physics, Centre for Medical Image Computing, UCL, London, UK.,Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Andre Altmann
- Department of Medical Physics, Centre for Medical Image Computing, UCL, London, UK
| | - Michael Suttie
- Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK.,Big Data Institute, Old Road Campus, University of Oxford, Oxford, UK
| | - Peter Hammond
- Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK.,Big Data Institute, Old Road Campus, University of Oxford, Oxford, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London.,Chalfont Centre for Epilepsy, Gerrards Cross, UK
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Fluctuating Asymmetry and Sexual Dimorphism in Human Facial Morphology: A Multi-Variate Study. Symmetry (Basel) 2021; 13. [PMID: 33664983 DOI: 10.3390/sym13020304] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Fluctuating asymmetry is often used as an indicator of developmental instability, and is proposed as a signal of genetic quality. The display of prominent masculine phenotypic features, which are a direct result of high androgen levels, is also believed to be a sign of genetic quality, as these hormones may act as immunosuppressants. Fluctuating asymmetry and masculinity are therefore expected to covary. However, there is lack of strong evidence in the literature regarding this hypothesis. Materials and methods In this study, we examined a large dataset of high-density 3D facial scans of 1260 adults (630 males and 630 females). We mapped a high-density 3D facial mask onto the facial scans in order to obtain a high number of quasi-landmarks on the faces. Multi-dimensional measures of fluctuating asymmetry were extracted from the landmarks using Principal Component Analysis, and masculinity/femininity scores were obtained for each face using Partial Least Squares. The possible correlation between these two qualities was then examined using Pearson's coefficient and Canonical Correlation Analysis. Results We found no correlation between fluctuating asymmetry and masculinity in men. However, a weak but significant correlation was found between average fluctuating asymmetry and masculinity in women, in which feminine faces had higher levels of fluctuating asymmetry on average. This correlation could possibly point to genetic quality as an underlying mechanism for both asymmetry and masculinity; however, it might also be driven by other fitness or life history traits, such as fertility. Conclusions Our results question the idea that fluctuating asymmetry and masculinity should be (more strongly) correlated in men, which is in line with the recent literature. Future studies should possibly focus more on the evolutionary relevance of the observed correlation in women.
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Boulan L, Léopold P. What determines organ size during development and regeneration? Development 2021; 148:148/1/dev196063. [PMID: 33431590 DOI: 10.1242/dev.196063] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The sizes of living organisms span over 20 orders of magnitude or so. This daunting observation could intimidate researchers aiming to understand the general mechanisms controlling growth. However, recent progress suggests the existence of principles common to organisms as diverse as fruit flies, mice and humans. As we review here, these studies have provided insights into both autonomous and non-autonomous mechanisms controlling organ growth as well as some of the principles underlying growth coordination between organs and across bilaterally symmetrical organisms. This research tackles several aspects of developmental biology and integrates inputs from physics, mathematical modelling and evolutionary biology. Although many open questions remain, this work also helps to shed light on medically related conditions such as tissue and limb regeneration, as well as metabolic homeostasis and cancer.
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Affiliation(s)
- Laura Boulan
- Institut Curie, PSL University, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology unit, 75005 Paris, France
| | - Pierre Léopold
- Institut Curie, PSL University, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology unit, 75005 Paris, France
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Currò G, Bilello G, Messina P, Scardina GA. Transverse Asymmetries of the Maxilla Even in Healthy and Apparently Symmetrical Subjects. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:E446. [PMID: 33429919 PMCID: PMC7826829 DOI: 10.3390/ijerph18020446] [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] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/30/2020] [Accepted: 01/04/2021] [Indexed: 11/17/2022]
Abstract
In the formulation of an orthodontic treatment plan, the three-dimensional analysis of the dental arches represents a fundamental moment for the evaluation of all the morphological parameters necessary in order to have a correct and complete diagnosis. In this regard, the study of the dental arches on the horizontal plane is sometimes neglected or not thorough enough. When evaluating the transverse dimensions of the dental upper arche, the presence of an asymmetry is frequently found, and it means that an hemiarch is larger than the other. Furthermore, any variation in one of the three planes of space always involves an alteration also on the other two planes in order to have compensation. The morphology of a bone segment depends on various factors, mainly genetical, acquired and environmental. Regarding the environmental factors, the function determines the morphology, but this in turn determines the function. In the case of unilateral mastication, the upper maxilla will be asymmetrical, so growing patients will have compensation on other skull bones. From these considerations arises the need for a careful study of the horizontal plane of the maxilla in the presence of a malocclusion during diagnostic evaluations. These asymmetries, however, must be evaluated and quantified in the diagnostic phase in order to formulate a correct plan of treatment. The aim of this work is to demonstrate that there are almost always transverse asymmetries of the maxilla, albeit of a slight entity, even in healthy and apparently symmetrical subjects.
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Affiliation(s)
| | | | | | - Giuseppe Alessandro Scardina
- Department of Surgical, Oncological and Stomatological Disciplines (DiChirOnS), University of Palermo, 90133 Palermo, Italy; (G.C.); (G.B.); (P.M.)
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O'Donnell L, Moes E. Increased dental fluctuating asymmetry is associated with active skeletal lesions, but not mortality hazards in the precontact Southwest United States. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 175:156-171. [PMID: 33368176 DOI: 10.1002/ajpa.24202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/24/2020] [Accepted: 12/05/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE This study examines whether individuals with higher dental fluctuating asymmetry (DFA) are frailer than those with lower DFA, by examining whether increased DFA is associated with skeletal lesion formation. SUBJECTS AND METHODS 150 individuals with permanent teeth and 64 individuals with deciduous teeth. All individuals are Ancestral Puebloans from archaeological sites in modern-day New Mexico. We estimate DFA in three ways: (a) deciduous DFA only, (b) permanent DFA only, and (c) a composite of permanent and deciduous DFA. We analyzed DFA alongside lesion status for cribra orbitalia (CO) and porotic hyperostosis (PH), as well as the presence/absence of enamel hypoplasia (EH). All stress indicators were further analyzed for their impact on mortality hazards. RESULTS We find that individuals with active CO and PH lesions have increased DFA, while those with healed lesions have lower DFA. We found no relationship between EH and DFA. Further, DFA alone does not predict individual mortality but CO does. CONCLUSIONS Individuals with increased DFA are frailer and therefore, less capable of buffering themselves against perturbations to their health than those with lower DFA. All results indicate that individuals in this study with lower DFA were more successful in buffering themselves against random environmental impacts during childhood. While DFA alone does not predict mortality hazard, its relationship to lesion status (lower DFA in individuals with healed lesions) indicates that it would be a valuable addition to studies of health and stress.
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Affiliation(s)
- Lexi O'Donnell
- Department of Sociology and Anthropology, University of Mississippi, Oxford, Mississippi, USA
| | - Emily Moes
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
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Breaking Symmetry: Fluctuating Asymmetry and Geometric Morphometrics as Tools for Evaluating Developmental Instability under Diverse Agroecosystems. Symmetry (Basel) 2020. [DOI: 10.3390/sym12111789] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fluctuating asymmetry (FA), in contrast with other asymmetries, is the bilateral asymmetry that represents small, random developmental differences between right and left sides. After nearly a century of using traditional morphometrics in the estimation of FA, geometric morphometrics (GM) now provides new insights into the use of FA as a tool, especially for assessing environmental and developmental stress. Thus, it will be possible to assess adaptation to various environmental stressors as particular triggers for unavoidable selection pressures. In this review, we describe measures of FA that use geometric morphometrics, and we include a flow chart of the methodology. We also describe how this combination (GM + FA) has been tested in several agroecosystems. Nutritional stress, temperature, chemical pollution, and population density are known stressors experienced by populations in agroecosystems.
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Li Y, Li L, Shi J, Tu J, Niu L, Hu X. Positional Changes of Mandibular Canal Before and After Decompression of Cystic Lesions in the Mandible. J Oral Maxillofac Surg 2020; 79:854-862. [PMID: 33166521 DOI: 10.1016/j.joms.2020.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 10/04/2020] [Accepted: 10/05/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE Significant displacement of the mandibular canal (MC), which occurs frequently in extensive mandibular cystic lesion cases, may raise the risk of inferior alveolar neurovascular bundle injury in surgery. The aim of the present study was to measure the association between positional changes of the MC and the direction (in the coronal plane) of bone expansion of cystic lesions in the mandible. PATIENTS AND METHODS We performed a retrospective study of patients who had undergone decompression and enucleation surgery from January 2014 to December 2018. Based on coronal planes of cone-beam computerized tomography, the centroids of the expanded mandibles were calculated and considered markers for evaluation of the directions of bone expansion. In addition, the changes in the position of the MC before decompression and enucleation were measured and compared. A Cartesian coordinate system was introduced in this study to illustrate the relationship of positional changes between the displacement of the MC and expansion of the mandible in a straightforward manner. Statistical analysis was performed using the paired t test, unpaired t test, one-way analysis of variance or linear regression as appropriate. RESULTS Thirty-six patients with an average age of 29.8 years (14 men, 22 women) who received treatment of decompression and enucleation for mandibular cystic lesions were included in this study. The MCs were displaced in the direction toward the lower edge of the mandible and opposite to the direction of mandibular expansion. In addition, the MCs were relocated close to their original location by 1.67 ± 1.45 mm (mean ± standard deviation) approximately 1 year after decompression, accounting for 22.66% of the total displacement. CONCLUSIONS In mandibular cystic lesion cases, the MCs tend to displace opposite to the direction of mandibular expansion and relocate less after decompression.
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Affiliation(s)
- Yuncong Li
- Attending Staff, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lifeng Li
- Attending Staff, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Jingyi Shi
- Resident, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Junbo Tu
- Professor, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Lin Niu
- Professor, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaoyi Hu
- Professor, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, China.
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Kordsmeyer TL, Thies YTK, Ekrami O, Stern J, Schild C, Spoiala C, Claes P, Van Dongen S, Penke L. No evidence for an association between facial fluctuating asymmetry and vocal attractiveness in men or women. EVOLUTIONARY HUMAN SCIENCES 2020; 2:e35. [PMID: 37588384 PMCID: PMC10427465 DOI: 10.1017/ehs.2020.36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Facial fluctuating asymmetry (FA), presumably a proxy measure of developmental instability, has been proposed to inversely relate to vocal attractiveness, which may convey information on heritable fitness benefits. Using an improved method of measuring facial FA, we sought to replicate two recent studies that showed an inverse correlation of facial FA with vocal attractiveness. In two samples of men (N = 165) and women (N = 157), we investigated the association of automatically measured facial FA based on 3D face scans with male and female observer-rated attractiveness of voice recordings. No significant associations were found for men or women, also when controlling for facial attractiveness, age, and body mass index. Equivalence tests show that effect sizes were significantly smaller than previous meta-analytic effects, providing robust evidence against a link of facial FA with vocal attractiveness. Thus, our study contradicts earlier findings that vocal attractiveness may signal genetic quality in humans via an association with FA.
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Affiliation(s)
- Tobias L. Kordsmeyer
- Department of Psychology and Leibniz Science Campus, Primate Cognition, University of Goettingen, Gosslerstr. 14, 37073Goettingen, Germany
| | - Yasmin T. K. Thies
- Department of Psychology and Leibniz Science Campus, Primate Cognition, University of Goettingen, Gosslerstr. 14, 37073Goettingen, Germany
| | - Omid Ekrami
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610Antwerp, Belgium
| | - Julia Stern
- Department of Psychology and Leibniz Science Campus, Primate Cognition, University of Goettingen, Gosslerstr. 14, 37073Goettingen, Germany
| | - Christoph Schild
- Department of Psychology, University of Copenhagen, Øster Farimagsgade 2A, 1353Copenhagen, Denmark
| | - Cristina Spoiala
- Nivel, Netherlands Institute for Health Services Research, Otterstraat 118, 3513 CR Utrecht, The Netherlands
| | - Peter Claes
- Department of Electrical Engineering–ESAT & Department of Human Genetics, KU Leuven, Herestraat 49, 3000Leuven, Belgium
| | - Stefan Van Dongen
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610Antwerp, Belgium
| | - Lars Penke
- Department of Psychology and Leibniz Science Campus, Primate Cognition, University of Goettingen, Gosslerstr. 14, 37073Goettingen, Germany
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Ekrami O, Claes P, White JD, Weinberg SM, Marazita ML, Walsh S, Shriver MD, Dongen SV. A Multivariate Approach to Determine the Dimensionality of Human Facial Asymmetry. Symmetry (Basel) 2020; 12:348. [PMID: 33569240 PMCID: PMC7872143 DOI: 10.3390/sym12030348] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Many studies have suggested that developmental instability (DI) could lead to asymmetric development, otherwise known as fluctuating asymmetry (FA). Several attempts to unravel the biological meaning of FA have been made, yet the main step in estimating FA is to remove the effects of directional asymmetry (DA), which is defined as the average bilateral asymmetry at the population level. Here, we demonstrate in a multivariate context that the conventional method of DA correction does not adequately compensate for the effects of DA in other dimensions of asymmetry. This appears to be due to the presence of between-individual variation along the DA dimension. Consequently, we propose to decompose asymmetry into its different orthogonal dimensions, where we introduce a new measure of asymmetry, namely fluctuating directional asymmetry (F-DA). This measure describes individual variation in the dimension of DA, and can be used to adequately correct the asymmetry measurements for the presence of DA. We provide evidence that this measure can be useful in disentangling the different dimensions of asymmetry, and further studies on this measure can provide valuable insight into the underlying biological processes leading to these different asymmetry dimensions.
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Affiliation(s)
- Omid Ekrami
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, 2610 Antwerp, Belgium; stefan
| | - Peter Claes
- Department of Electrical Engineering, ESAT/PSI, KU Leuven, 3000 Leuven, Belgium
- Medical Imaging Research Center, UZ Leuven, 3000 Leuven, Belgium
- Department of Human Genetics, KU Leuven, 3000 Leuven, Belgium
| | - Julie D. White
- Department of Anthropology, Pennsylvania State University, University Park, State College, PA 16801, USA
| | - Seth M. Weinberg
- Department of Oral Biology, Center for Craniofacial and Dental Genetics, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Mary L. Marazita
- Department of Oral Biology, Center for Craniofacial and Dental Genetics, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Susan Walsh
- Department of Biology, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN 46202, USA
| | - Mark D. Shriver
- Department of Anthropology, Pennsylvania State University, University Park, State College, PA 16801, USA
| | - Stefan Van Dongen
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, 2610 Antwerp, Belgium; stefan
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Stephan-Otto C, Lombardini F, Núñez C, Senior C, Ochoa S, Usall J, Brébion G. Fluctuating asymmetry in patients with schizophrenia is related to hallucinations and thought disorganisation. Psychiatry Res 2020; 285:112816. [PMID: 32036154 DOI: 10.1016/j.psychres.2020.112816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 11/26/2022]
Abstract
Fluctuating asymmetry represents the degree to which the right and left side of the body are asymmetrical, and is a sign of developmental instability. Higher levels of fluctuating asymmetry have been observed in individuals within the schizophrenia spectrum. We aimed to explore the associations of fluctuating asymmetry with psychotic and affective symptoms in schizophrenia patients, as well as with propensity to these symptoms in non-clinical individuals. A measure of morphological fluctuating asymmetry was calculated for 39 patients with schizophrenia and 60 healthy individuals, and a range of clinical and subclinical psychiatric symptoms was assessed. Regression analyses of the fluctuating asymmetry measure were conducted within each group. In the patient cohort, fluctuating asymmetry was significantly associated with the hallucination and thought disorganisation scores. T-test comparisons revealed that the patients presenting either hallucinations or thought disorganisation were significantly more asymmetrical than were the healthy individuals, while the patients without these key symptoms were equivalent to the healthy individuals. A positive association with the anxiety score emerged in a subsample of 36 healthy participants who were rated on affective symptoms. These findings suggest that fluctuating asymmetry may be an indicator of clinical hallucinations and thought disorganisation rather than an indicator of schizophrenia disease.
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Affiliation(s)
- Christian Stephan-Otto
- Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | | | - Christian Núñez
- Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain
| | - Carl Senior
- School of Life & Health Sciences, Aston University, Birmingham, UK; Research and Development Unit - Parc Sanitari Sant Joan de Déu, c/ Dr. Antoni Pujadas, 42, 08830 - Sant Boi de Llobregat, Barcelona, Spain
| | - Susana Ochoa
- Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Judith Usall
- Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Gildas Brébion
- Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.
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Wijerathne BTB, Meier RJ, Salgado SS, Agampodi SB. Qualitative and quantitative dermatoglyphics of chronic kidney disease of unknown origin (CKDu) in Sri Lanka. J Physiol Anthropol 2020; 39:1. [PMID: 31952553 PMCID: PMC6967092 DOI: 10.1186/s40101-019-0207-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/11/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Dermatoglyphics has been used widely in fields of medicine as a non-invasive diagnostic tool and an early assessment of risk for certain medical conditions. It reflects disturbances in fetal development during early prenatal weeks 14-22 when fingerprints develop. Dermatoglyphic asymmetry has been used to measure developmental instability during a specific period of human fetal development. Thus, the present study was planned to investigate whether digital and palmar dermatoglyphics of chronic kidney disease of unknown origin (CKDu) patients in Sri Lanka are different from healthy people. METHODS A case control study was carried out among CKDu patients (90 males, 90 females) from a CKDu endemic area and gender-matched two control groups; one group from a CKDu endemic region (90 males, 90 females) and another group from a CKDu non-endemic region (90 males, 90 females). Dermatoglyphics were obtained using photographic methods. Both qualitative and quantitative dermatoglyphic variables were defined and analyzed according to standard criteria. Both directional (DA) and fluctuating asymmetry (FA) were assessed. RESULTS Several qualitative dermatoglyphic variables had significant association with CKDu. The triradii a1 variable was less evident in palms of CKDu cases in both genders when compared to both control groups. The FA of pattern discordance (right vs left hands) between CKDu cases and control group were significant in several digits. The FA of the ridge count was found significant in several digits, and also significant for A-B ridge count and total ridge count. CONCLUSION Based on these results, it is proposed that the mechanisms responsible for the development of CKDu might be associated with those responsible for FA observed in CKDu patients. Accordingly, a diagnostic tool based on FA could be developed for predicting risk prior to the development of CKDu.
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Affiliation(s)
| | - Robert John Meier
- Department of Anthropology, Indiana University, Bloomington, IN, USA
| | | | - Suneth Buddhika Agampodi
- Department of Community Medicine, Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka, Saliyapura, 50008, Sri Lanka
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Kočnar T, Saribay SA, Kleisner K. Perceived attractiveness of Czech faces across 10 cultures: Associations with sexual shape dimorphism, averageness, fluctuating asymmetry, and eye color. PLoS One 2019; 14:e0225549. [PMID: 31751432 PMCID: PMC6872208 DOI: 10.1371/journal.pone.0225549] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/06/2019] [Indexed: 01/17/2023] Open
Abstract
Research on the perception of faces typically assumes that there are some universal values of attractiveness which are shared across individuals and cultures. The perception of attractiveness may, however, vary across cultures due to local differences in both facial morphology and standards of beauty. To examine cross-cultural consensus in the ratings of attractiveness, we presented a set of 120 non-manipulated photographs of Czech faces to ten samples of raters from both European (Czech Republic, Estonia, Sweden, Romania, Turkey, Portugal) and non-European countries (Brazil, India, Cameroon, Namibia). We examined the relative contribution of three facial markers (sexual shape dimorphism, averageness, fluctuating asymmetry) to the perception of attractiveness as well as the possible influence of eye color, which is a locally specific trait. In general, we found that both male and female faces which were closer to the average and more feminine in shape were regarded as more attractive, while fluctuating asymmetry had no effect. Despite a high cross-cultural consensus on attractiveness standards, significant differences in the perception of attractiveness seem to be related to the level of socio-economic development (as measured by the Human Development Index, HDI). Attractiveness ratings by raters from low-HDI countries (India, Cameroon, Namibia) converged less with ratings from Czech Republic than ratings from high-HDI countries (European countries and Brazil). With respect to eye color, some local patterns emerged which we discuss as a consequence of negative frequency-dependent selection.
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Affiliation(s)
- Tomáš Kočnar
- Department of Philosophy and History of Science, Charles University in Prague, Prague, Czech Republic
| | - S. Adil Saribay
- Department of Psychology, Boğaziçi University, Istanbul, Turkey
| | - Karel Kleisner
- Department of Philosophy and History of Science, Charles University in Prague, Prague, Czech Republic
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Nagano H, Sarashina E, Sparrow W, Mizukami K, Begg R. General Mental Health Is Associated with Gait Asymmetry. SENSORS 2019; 19:s19224908. [PMID: 31717634 PMCID: PMC6891551 DOI: 10.3390/s19224908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 11/16/2022]
Abstract
Wearable sensors are being applied to real-world motion monitoring and the focus of this work is assessing health status and wellbeing. An extensive literature has documented the effects on gait control of impaired physical health, but in this project, the aim was to determine whether emotional states associated with older people's mental health are also associated with walking mechanics. If confirmed, wearable sensors could be used to monitor affective responses. Lower limb gait mechanics of 126 healthy individuals (mean age 66.2 ± 8.38 years) were recorded using a high-speed 3D motion sensing system and they also completed a 12-item mental health status questionnaire (GHQ-12). Mean step width and minimum foot-ground clearance (MFC), indicative of tripping risk, were moderately correlated with GHQ-12. Ageing and variability (SD) of gait parameters were not significantly correlated with GHQ-12. GHQ-12 scores were, however, highly correlated with left-right gait control, indicating that greater gait symmetry was associated with better mental health. Maintaining good mental health with ageing may promote safer gait and wearable sensor technologies could be applied to gait asymmetry monitoring, possibly using a single inertial measurement unit attached to each shoe.
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Affiliation(s)
- Hanatsu Nagano
- Institute for Health and Sport (IHeS), Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia; (H.N.); (W.S.)
| | - Eri Sarashina
- Graduate School of Comprehensive Human Sciences, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan; (E.S.); (K.M.)
| | - William Sparrow
- Institute for Health and Sport (IHeS), Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia; (H.N.); (W.S.)
| | - Katsuyoshi Mizukami
- Graduate School of Comprehensive Human Sciences, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan; (E.S.); (K.M.)
| | - Rezaul Begg
- Institute for Health and Sport (IHeS), Victoria University, P.O. Box 14428, Melbourne, VIC 8001, Australia; (H.N.); (W.S.)
- Correspondence: ; Tel.: +61-3-9919-1116
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Boutrus M, Gilani SZ, Alvares GA, Maybery MT, Tan DW, Mian A, Whitehouse AJO. Increased facial asymmetry in autism spectrum conditions is associated with symptom presentation. Autism Res 2019; 12:1774-1783. [PMID: 31225951 DOI: 10.1002/aur.2161] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/05/2019] [Indexed: 01/23/2023]
Abstract
A key research priority in the study of autism spectrum conditions (ASC) is the discovery of biological markers that may help to identify and elucidate etiologically distinct subgroups. One physical marker that has received increasing research attention is facial structure. Although there remains little consensus in the field, findings relating to greater facial asymmetry (FA) in ASC exhibit some consistency. As there is growing recognition of the importance of replicatory studies in ASC research, the aim of this study was to investigate the replicability of increased FA in autistic children compared to nonautistic peers. Using three-dimensional photogrammetry, this study examined FA in 84 autistic children, 110 typically developing children with no family history of the condition, and 49 full siblings of autistic children. In support of previous literature, significantly greater depth-wise FA was identified in autistic children relative to the two comparison groups. As a further investigation, increased lateral FA in autistic children was found to be associated with greater severity of ASC symptoms on the Autism Diagnostic Observation Schedule, second edition, specifically related to repetitive and restrictive behaviors. These outcomes provide an important and independent replication of increased FA in ASC, as well as a novel contribution to the field. Having confirmed the direction and areas of increased FA in ASC, these findings could motivate a search for potential underlying brain dysmorphogenesis. Autism Res 2019, 12: 1774-1783. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: This study looked at the amount of facial asymmetry (FA) in autistic children compared to typically developing children and children who have siblings with autism. The study found that autistic children, compared to the other two groups, had greater FA, and that increased FA was related to greater severity of autistic symptoms. The face and brain grow together during the earliest stages of development, and so findings of facial differences in autism might inform future studies of early brain differences associated with the condition.
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Affiliation(s)
- Maryam Boutrus
- Telethon Kids Institute, University of Western Australia, Perth, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia.,School of Psychological Science, University of Western Australia, Perth, Australia
| | - Syed Zulqarnain Gilani
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia.,School of Science, Edith Cowan University, Perth, Australia
| | - Gail A Alvares
- Telethon Kids Institute, University of Western Australia, Perth, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
| | - Murray T Maybery
- School of Psychological Science, University of Western Australia, Perth, Australia
| | - Diana Weiting Tan
- Telethon Kids Institute, University of Western Australia, Perth, Australia.,School of Psychological Science, University of Western Australia, Perth, Australia
| | - Ajmal Mian
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia
| | - Andrew J O Whitehouse
- Telethon Kids Institute, University of Western Australia, Perth, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
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Number of friends and self-perception among Jamaican children: the role of attractiveness and fluctuating asymmetry. J Biosoc Sci 2019; 52:184-197. [DOI: 10.1017/s0021932019000373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThe role that physical attractiveness and fluctuating asymmetry (FA), a measure of developmental instability, play in self-perception and peer associations were explored in a well-studied cohort of Jamaican children using a novel research paradigm where subjects were already known to each other for extensive periods of time. The results showed that how attractive a child was perceived by others was significantly positively correlated with self-ratings of attractiveness. Contrary to findings from WEIRD (Western, Educated, Industrialized, Rich, Democratic) samples, the study found a reversal in the sex differences in self-perceived attractiveness and self-esteem, where Jamaican females rate themselves more attractive and report higher self-esteem than do males. Attractiveness also predicts overall popularity, as measured by desirability as a friend and the percentage of peers who choose an individual as a friend. Attractive individuals of both sexes were chosen more often as ‘friends’. A significant correlation was also found between an individual’s FA and the average FA of those chosen as friends. However, the effect was primarily due to preferences by males for female friends possessing similar levels of FA, which could be an effective strategy in reducing future mating effort.
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de Lussanet MHE. Opposite asymmetries of face and trunk and of kissing and hugging, as predicted by the axial twist hypothesis. PeerJ 2019; 7:e7096. [PMID: 31211022 PMCID: PMC6557252 DOI: 10.7717/peerj.7096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022] Open
Abstract
The contralateral organization of the forebrain and the crossing of the optic nerves in the optic chiasm represent a long-standing conundrum. According to the Axial Twist Hypothesis (ATH) the rostral head and the rest of the body are twisted with respect to each other to form a left-handed half turn. This twist is the result, mainly, of asymmetric, twisted growth in the early embryo. Evolutionary selection tends to restore bilateral symmetry. Since selective pressure will decrease as the organism approaches symmetry, we expected a small control error in the form of a small, residual right-handed twist. We found that the mouth-eyes-nose (rostral head) region shows a left-offset with respect to the ears (posterior head) by up to 0.8° (P < 0.01, Bonferroni-corrected). Moreover, this systematic aurofacial asymmetry was larger in young children (on average up to 3°) and reduced with age. Finally, we predicted and found a right-sided bias for hugging (78%) and a left-sided bias for kissing (69%). Thus, all predictions were confirmed by the data. These results are all in support of the ATH, whereas the pattern of results is not (or only partly) explained by existing alternative theories. As of the present results, the ATH is the first theory for the contralateral forebrain and the optic chiasm whose predictions have been tested empirically. We conclude that humans (and all other vertebrates) are fundamentally asymmetric, both in their anatomy and their behavior. This supports the thesis that the approximate bilateral symmetry of vertebrates is a secondary feature, despite their being bilaterians.
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Affiliation(s)
- Marc H E de Lussanet
- Department of Movement Science, University of Münster, Münster, Germany.,Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, Germany
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Biological Bases of Beauty Revisited: The Effect of Symmetry, Averageness, and Sexual Dimorphism on Female Facial Attractiveness. Symmetry (Basel) 2019. [DOI: 10.3390/sym11020279] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The factors influencing human female facial attractiveness—symmetry, averageness, and sexual dimorphism—have been extensively studied. However, recent studies, using improved methodologies, have called into question their evolutionary utility and links with life history. The current studies use a range of approaches to quantify how important these factors actually are in perceiving attractiveness, through the use of novel statistical analyses and by addressing methodological weaknesses in the literature. Study One examines how manipulations of symmetry, averageness, femininity, and masculinity affect attractiveness using a two-alternative forced choice task, finding that increased masculinity and also femininity decrease attractiveness, compared to unmanipulated faces. Symmetry and averageness yielded a small and large effect, respectively. Study Two utilises a naturalistic ratings paradigm, finding similar effects of averageness and masculinity as Study One but no effects of symmetry and femininity on attractiveness. Study Three applies geometric face measurements of the factors and a random forest machine learning algorithm to predict perceived attractiveness, finding that shape averageness, dimorphism, and skin texture symmetry are useful features capable of relatively accurate predictions, while shape symmetry is uninformative. However, the factors do not explain as much variance in attractiveness as the literature suggests. The implications for future research on attractiveness are discussed.
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Pecháček P, Stella D, Kleisner K. A morphometric analysis of environmental dependences between ultraviolet patches and wing venation patterns in Gonepteryx butterflies (Lepidoptera, Pieridae). Evol Ecol 2019. [DOI: 10.1007/s10682-019-09969-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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50
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Functional Asymmetry and Fingerprint Features of Left-Handed and Right-Handed Young Yakuts (Mongoloid Race, North-Eastern Siberia). Symmetry (Basel) 2018. [DOI: 10.3390/sym10120728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
An ethnically homogeneous group of Yakuts (Mongoloid race, Northeast Asia), aged 18–31, was studied to characterize the diversity of particular features between left- and right-handed individuals. A total of 52 left-handed (32 women and 20 men) and 100 right-handed (50 women and 50 men) individuals were studied. Testing included two sets of questions and tasks, dynamometry of the right and left hand, and fingerprint analysis. Left-handed and right-handed people were found to differ in functional asymmetry of psychophysiological and motor reactions. Right-handers were characterized by higher intragroup similarity, while, among left-handers, greater dispersion of these traits was observed. Asymmetry in hand grip strength was less pronounced in the left-handed people than in the right-handed; this difference was statistically significant, and the difference was greater in men than in women. This suggests that the non-dominant hand in the left-handed people was subjected to a greater load and indicates the forced adaptation of the left-handed people to “dextrastress”. No significant difference between sexes was found when analyzing fingerprint patterns. Left-handers had arches significantly more often than right-handers. Radial loops were most often found on the index finger, and, in the left-handers, their occurrence was significantly higher on three to five fingers of the left hand compared with the right-handers. The levels of fluctuating asymmetry in left-handers and right-handers were similar.
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