scholarly journals Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

2020 ◽  
Author(s):  
Carolyn R. Hodges-Simeon ◽  
Graham Albert ◽  
George B. Richardson ◽  
Timothy S. McHale ◽  
Seth M. Weinberg ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Current Evidence ◽  
Facial Morphology ◽  
Facial Growth ◽  
Height Ratio ◽  
Lower Face ◽  
Male Adolescents ◽  
Classic Pattern ◽  
Facial Development

AbstractSexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements collected from males and females aged 3 to 40 (Study 1; US, n=2449), and 7 to 21 (Study 2; Bolivia, n=179) were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e. differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs—greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the 2D sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative growth in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI.

scholarly journals Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0240284
Author(s):  
Carolyn R. Hodges-Simeon ◽  
Graham Albert ◽  
George B. Richardson ◽  
Timothy S. McHale ◽  
Seth M. Weinberg ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Relative Elongation ◽  
Current Evidence ◽  
Multivariate Techniques ◽  
Facial Morphology ◽  
Facial Growth ◽  
Height Ratio ◽  
Lower Face ◽  
Males And Females

Sexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements were collected from 3D surface images of males and females aged 3 to 40 (Study 1; US European-descent, n = 2449), and from 2D photographs of males and females aged 7 to 21 (Study 2; Bolivian Tsimane, n = 179), which were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e., differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs—greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the Bolivian Tsimane sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative elongation in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI. Researchers should also compare ratio approaches with multivariate techniques, such as geometric morphometrics, to examine whether the latter have greater utility for understanding the evolution of facial sexual dimorphism.

scholarly journals Epigallocatechin-3-Gallate Improves Facial Dysmorphology Associated with Down Syndrome

2018 ◽  
Author(s):  
John M. Starbuck ◽  
Sergi Llambrich ◽  
Ruben González ◽  
Julia Albaigès ◽  
Anna Sarlé ◽  
...  
Keyword(s):  
Down Syndrome ◽  
Chromosome 21 ◽  
Current Evidence ◽  
High Dose ◽  
Facial Morphology ◽  
Egcg Treatment ◽  
Health Promoting ◽  
Potential Benefits ◽  
Facial Development ◽  
First Time

AbstractIn Down syndrome (DS), the overall genetic imbalance caused by trisomy of chromosome 21 leads to a complex pleiotropic phenotype that involves a recognizable set of facial traits. Several studies have shown the potential of epigallocatechin-3-gallate (EGCG), a green tea flavanol, as a therapeutic tool for alleviating different developmental alterations associated with DS, such as cognitive impairment, skull dysmorphologies, and skeletal deficiencies. Here we provide for the first time experimental and clinical evidence of the potential benefits of EGCG treatment to facial morphology. Our results showed that mouse models treated with low dose of EGCG during pre- and postnatal development improved facial dysmorphology. However, the same treatment at high dose produced disparate facial morphology changes with an extremely wide and abnormal range of variation. Our observational study in humans revealed that EGCG treatment since early in development is associated with intermediate facial phenotypes and significant facial improvement scores. Overall, our findings suggest a potential beneficial effect of ECGC on facial development, which requires further research to pinpoint the optimal dosages of EGCG that reliably improve DS phenotypes. Current evidence warns against the non-prescribed intake of this supplement as a health-promoting measure.

Hard Palate Repair Timing and Facial Growth in Unilateral Cleft Lip and Palate: A Longitudinal Study

2006 ◽  
Vol 43 (5) ◽  
pp. 547-556 ◽  
Author(s):  
Yu-Fang Liao ◽  
Timothy J. Cole ◽  
Michael Mars
Keyword(s):  
Longitudinal Study ◽  
Hard Palate ◽  
Cleft Lip ◽  
Cleft Lip And Palate ◽  
Sri Lankan ◽  
Facial Morphology ◽  
Facial Growth ◽  
Clinical Notes ◽  
Timing Effect ◽  
Palate Repair

Objective: To investigate whether timing of hard palate repair had a significant effect on facial growth in patients with unilateral cleft lip and palate (UCLP). Design: Retrospective longitudinal study. Setting: Sri Lankan Cleft Lip and Palate Project. Patients: A total of 104 patients with nonsyndromic UCLP who had hard palate repair by age 13 years, with their 290 cephalometric radiographs taken after lip and palate repair. Main Outcome Measures: Clinical notes were used to record surgical treatment histories. Cephalometry was used to determine facial morphology and growth rate. Results: Timing of hard palate repair had a significant effect on the length and protrusion of the alveolar maxilla (PMP-A and SNA, respectively) and the anteroposterior alveolar jaw relation (ANB) at age 20 years but not on their growth rates. Conclusion: Timing of hard palate repair significantly affects the growth of the maxilla in patients with UCLP. Late hard palate repair has a smaller adverse effect than does early hard palate repair on the growth of the maxilla. This timing effect primarily affects the anteroposterior development of the maxillary dentoalveolus and is attributed to the development being undisturbed before closure of the hard palate.

scholarly journals Sex differences in age-to-maturation relate to sexual selection and adult sex ratios in birds

2020 ◽  
Vol 4 (1) ◽  
pp. 44-53
Author(s):  
Sergio Ancona ◽  
András Liker ◽  
M. Cristina Carmona-Isunza ◽  
Tamás Székely
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Sex Ratios

scholarly journals Maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width groups

2015 ◽  
Vol 09 (04) ◽  
pp. 490-499 ◽  
Author(s):  
Fazal Shahid ◽  
Mohammad Khursheed Alam ◽  
Mohd Fadhli Khamis
Keyword(s):  
Sex Differences ◽  
Sample Size ◽  
Analysis Of Variance ◽  
Significant Relation ◽  
Height Ratio ◽  
Mean Values ◽  
Comprehensive Management ◽  
Arch Width ◽  
Crown Width ◽  
Maxilla And Mandible

ABSTRACT Objective: To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups. Materials and Methods: The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups. Results: Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both. Conclusions: Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management.

The Role of Retinoids in Normal and Abnormal Embryonic Craniofacial Morphogenesis

1992 ◽  
Vol 4 (1) ◽  
pp. 93-109 ◽  
Author(s):  
Joy M. Richman
Keyword(s):  
Craniofacial Development ◽  
Facial Growth ◽  
Specific Effects ◽  
The Face ◽  
Facial Development ◽  
Lines Of Evidence ◽  
Craniofacial Morphogenesis

The objective of this article is to evaluate the role of retinoids in the developing head and face. This article covers two lines of evidence that strongly support a role for retinoids in craniofacial development. First, the specific effects of exogenous retinoids on the head and face are covered and mechanisms for the specificity discussed. Second, the function of endogenous retinoids in facial development is discussed in relation to the distribution of retinoid-binding substances in the face. Finally, the interaction of retinoids with other genes known to be expressed in the face as well as other factors required for facial growth is discussed.

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