Developmental pathways inferred from modularity, morphological integration and fluctuating asymmetry patterns in the human face.

Facial asymmetries are usually measured and interpreted as proxies to developmental noise. However, analyses focused on its developmental and genetic architecture are scarce. To advance on this topic, studies based on a comprehensive and simultaneous analysis of modularity, morphological integration and facial asymmetries including both phenotypic and genomic information are needed. Here we explore several modularity hypotheses on a sample of Latin American mestizos, in order to test if modularity and integration patterns differ across several genomic ancestry backgrounds. To do so, 4104 individuals were analyzed using 3D photogrammetry reconstructions and a set of 34 facial landmarks placed on each individual. We found a pattern of modularity and integration that is conserved across sub-samples differing in their genomic ancestry background. Specifically, a signal of modularity based on functional demands and organization of the face is regularly observed across the whole sample. Our results shed more light on previous evidence obtained from Genome Wide Association Studies performed on the same samples, indicating the action of different genomic regions contributing to the expression of the nose and mouth facial phenotypes. Our results also indicate that large samples including phenotypic and genomic metadata enable a better understanding of the developmental and genetic architecture of craniofacial phenotypes.

Correction: Socioeconomic Status Is Not Related with Facial Fluctuating Asymmetry: Evidence from Latin-American Populations.

[This corrects the article DOI: 10.1371/journal.pone.0169287.].

Socioeconomic Status Is Not Related with Facial Fluctuating Asymmetry: Evidence from Latin-American Populations.

The expression of facial asymmetries has been recurrently related with poverty and/or disadvantaged socioeconomic status. Departing from the developmental instability theory, previous approaches attempted to test the statistical relationship between the stress experienced by individuals grown in poor conditions and an increase in facial and corporal asymmetry. Here we aim to further evaluate such hypothesis on a large sample of admixed Latin Americans individuals by exploring if low socioeconomic status individuals tend to exhibit greater facial fluctuating asymmetry values. To do so, we implement Procrustes analysis of variance and Hierarchical Linear Modelling (HLM) to estimate potential associations between facial fluctuating asymmetry values and socioeconomic status. We report significant relationships between facial fluctuating asymmetry values and age, sex, and genetic ancestry, while socioeconomic status failed to exhibit any strong statistical relationship with facial asymmetry. These results are persistent after the effect of heterozygosity (a proxy for genetic ancestry) is controlled in the model. Our results indicate that, at least on the studied sample, there is no relationship between socioeconomic stress (as intended as low socioeconomic status) and facial asymmetries.

A genome-wide association scan implicates DCHS2, RUNX2, GLI3, PAX1 and EDAR in human facial variation.

We report a genome-wide association scan for facial features in ∼6,000 Latin Americans. We evaluated 14 traits on an ordinal scale and found significant association (P values<5 × 10(-8)) at single-nucleotide polymorphisms (SNPs) in four genomic regions for three nose-related traits: columella inclination (4q31), nose bridge breadth (6p21) and nose wing breadth (7p13 and 20p11). In a subsample of ∼3,000 individuals we obtained quantitative traits related to 9 of the ordinal phenotypes and, also, a measure of nasion position. Quantitative analyses confirmed the ordinal-based associations, identified SNPs in 2q12 associated to chin protrusion, and replicated the reported association of nasion position with SNPs in PAX3. Strongest association in 2q12, 4q31, 6p21 and 7p13 was observed for SNPs in the EDAR, DCHS2, RUNX2 and GLI3 genes, respectively. Associated SNPs in 20p11 extend to PAX1. Consistent with the effect of EDAR on chin protrusion, we documented alterations of mandible length in mice with modified Edar funtion.

A genome-wide association study identifies multiple loci for variation in human ear morphology.

Here we report a genome-wide association study for non-pathological pinna morphology in over 5,000 Latin Americans. We find genome-wide significant association at seven genomic regions affecting: lobe size and attachment, folding of antihelix, helix rolling, ear protrusion and antitragus size (linear regression P values 2 × 10(-8) to 3 × 10(-14)). Four traits are associated with a functional variant in the Ectodysplasin A receptor (EDAR) gene, a key regulator of embryonic skin appendage development. We confirm expression of Edar in the developing mouse ear and that Edar-deficient mice have an abnormally shaped pinna. Two traits are associated with SNPs in a region overlapping the T-Box Protein 15 (TBX15) gene, a major determinant of mouse skeletal development. Strongest association in this region is observed for SNP rs17023457 located in an evolutionarily conserved binding site for the transcription factor Cartilage paired-class homeoprotein 1 (CART1), and we confirm that rs17023457 alters in vitro binding of CART1.

Facial asymmetry and genetic ancestry in Latin American admixed populations.

Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer environmental and genetic factors affecting facial phenotypes. However, the genetic basis and environmental determinants of both asymmetry types is far from being completely known. The analysis of facial asymmetries in admixed individuals can be of help to characterize the impact of a genome's heterozygosity on the developmental basis of both fluctuating and directional asymmetries. Here we characterize the association between genetic ancestry and individual asymmetry on a sample of Latin-American admixed populations. To do so, three-dimensional (3D) facial shape attributes were explored on a sample of 4,104 volunteers aged between 18 and 85 years. Individual ancestry and heterozygosity was estimated using more than 730,000 genome-wide markers. Multivariate techniques applied to geometric morphometric data were used to evaluate the magnitude and significance of directional and fluctuating asymmetry (FA), as well as correlations and multiple regressions aimed to estimate the relationship between facial FA scores and heterozygosity and a set of covariates. Results indicate that directional and FA are both significant, the former being the strongest expression of asymmetry in this sample. In addition, our analyses suggest that there are some specific patterns of facial asymmetries characterizing the different ancestry groups. Finally, we find that more heterozygous individuals exhibit lower levels of asymmetry. Our results highlight the importance of including ancestry-admixture estimators, especially when the analyses are aimed to compare levels of asymmetries on groups differing on socioeconomic levels, as a proxy to estimate developmental noise.

Admixture in Latin America: geographic structure, phenotypic diversity and self-perception of ancestry based on 7,342 individuals.

The current genetic makeup of Latin America has been shaped by a history of extensive admixture between Africans, Europeans and Native Americans, a process taking place within the context of extensive geographic and social stratification. We estimated individual ancestry proportions in a sample of 7,342 subjects ascertained in five countries (Brazil, Chile, Colombia, México and Perú). These individuals were also characterized for a range of physical appearance traits and for self-perception of ancestry. The geographic distribution of admixture proportions in this sample reveals extensive population structure, illustrating the continuing impact of demographic history on the genetic diversity of Latin America. Significant ancestry effects were detected for most phenotypes studied. However, ancestry generally explains only a modest proportion of total phenotypic variation. Genetically estimated and self-perceived ancestry correlate significantly, but certain physical attributes have a strong impact on self-perception and bias self-perception of ancestry relative to genetically estimated ancestry.

Physical activity related to forced vital capacity and strength performance in a sample of young males and females.

To identify the extent of physical performance differences between active and sedentary subjects taking into account sexual dimorphism physical activity level was recorded by interview from a sample of 319 young university students of both sexes. Anthropometric variables and physical performance values were obtained. The sex factor was the main variable explaining the differences in physical performance between active and sedentary young. Also contributors to those differences were forced vital capacity (FVC), heart rate after exercise and rest heart rate, together with the explosive component of strength (vertical jump). The effect of physical activity was shown in the increment of FVC and the decrease of resting heart rate. In the overall sample, heart rate after exercise, either in active males or active females, was lowered with respect to the sedentary subjects, showing that active females experienced a greater cardiovascular benefit following adaptation to training than sedentary.

Seguridad alimentaria en los hogares de Acandi: La disponibilidad de los alimentos como indicador de suficiencia alimentaria / Food security in households from Acandi: food availability as a mirror of food sufficiency

Objetivo: Analizar la variedad y suficiencia de alimentos disponibles en una semana en los hogares del área rural y urbana de Acandí, Chocó (Colombia). Tipo de estudio: Descriptivo de prevalencia. Metodología: Se estimó una muestra representativa, con una confianza del 95 por ciento y un error del 5 por ciento, constituida por 326 hogares, para indagar sobre los alimentos disponibles en el hogar en la última semana. Se analizó la diferencia de medias de alimentos diferentes disponibles según el área geográfica, la proporción de hogares con alimentos disponibles de cada grupo y el número de alimentos diferentes a su interior, la diferencia de medias de la disponibilidad en gramos per cápita/día de cada grupo y la adecuación promedio per cápita/día de está disponibilidad, según el área. Resultados: Para una semana la disponibilidad promedio de alimentos diferentes fue de 23±7 y 29±7 (p<0,001) en los hogares rurales y urbanos respectivamente. Una proporción alta de hogares urbanos y rurales dispusieron de todos los grupos, con baja variedad a su interior. La disponibilidad en gramos per cápita/día no presentó diferencias estadísticamente significantes entre el área rural y urbana, salvo en los grupos de leches (p<0,001), verduras (p=0,012), tubérculos y plátanos (p<0,001) y grasas (p<0,001), siendo la adecuación de esta disponibilidad baja, excepto para el grupo de azúcares y grasas. Conclusión: El hecho que los hogares de Acandí dispongan de todos los grupos de alimentos, no es condición suficiente para garantizar la seguridad alimentaria de sus integrantes, dada la poca variedad de alimentos que conforman cada grupo y la baja disponibilidad en gramos per cápita/día.

Fat distribution in relation to sex and socioeconomic status in children 4-19 years.

Fat distribution was studied in an urban sample of boys and girls 4.5 to 19.5 years from the Basque province of Biscay by means of Principal Component Analysis (PCA) of five skinfolds. The PCA extracted four components, which explained 99.1% of the total variance. The first principal component revealed strong stability across age and sex, and was related to a pattern of central body fat distribution. The three other components, upper-lower trunk fat, lateral-medial trunk fat, and upper-lower extremity fat, showed poor stability due largely to the influence of age and, to a lesser degree, sex. In both sexes, individual scores of the four factors did not show multivariate differences by socioeconomic status when a MANOVA with age, age2 and age3 as covariates was done. Nevertheless, the first factor scores were significantly higher only in the poorer socioeconomic group of girls. The results are explained in the context of either different lifestyles related to socioeconomic status, a protective effect against environmental stress on urban males, or greater plasticity of trunk fat relative to extremity fat in females. Am. J. Hum. Biol. 10:799-806, 1998. © 1998 Wiley-Liss, Inc.

Comparative study of statural growth in Spanish populations.

Regional differences in the growth of Spanish children were studied by fitting the Preece-Baines Model I to cross-sectional stature data. The function parameters and derived biological variables were used to compare children from seven different studies. Regional differences in growth are interpreted as a result of a geographic variation among Spanish provinces in demographic, public health and nutritional conditions. There are differences between urban samples depending on region. Adult stature (h1 ) and the pattern of growth differ between urban and rural populations from the interior lands. Males from urban Extremadura, Barcelona and the Basque Country show the tallest adult statures. Adult statures of males from Segovia, Extremadura emigrants and Cuenca are not only the lowest, but the growth pattern shows delay in estimated ages at take-off and PHV compared to the other populations. Estimated age at PHV is later for all male samples compared to Vizcaya, except for the sample of Barcelona-I. Females from Barcelona-II, Segovia and the Basque Country show the tallest adult statures (h1 ). All of the female samples, except that of urban Extremadura, have an earlier estimated age at PHV compared to the sample from Vizcaya. © 1995 Wiley-Liss, Inc.

Somatotype related to centripetal fat patterning of 8- to 19-year-old Basque boys and girls.

The association between fat distribution and Heath-Carter anthropometric somatotypes was studied in a sample of Basque children and youth aged 8-19 years. About mid-adolescence, mean somatotype of Basque males changed, diminishing in endomorphy and mesomorphy, and increasing slightly in ectomorphy. For the same period, reduced mesomorphy was the most striking change in the female mean somatotype; meanwhile, there was an increase in endomorphy and a decrease in ectomorphy. Two groups of fat distribution were identified: centripetal and peripheral. Centripetal fat increased with age in both sexes. Fat distribution groups showed the following characteristics: a) mean somatotypes of centripetal and peripheral subjects were significantly different; b) centripetal boys and girls were extreme endomorphs prior to adolescent somatotype change; c) centripetal girls showed high ratings of endomorphy after adolescence; d) mesomorphy was related to a centripetal fat distribution pattern in both sexes; e) using the BMI as a criterion of obesity, only 16.3% of centripetal males and 21.8% of centripetal females were classified as obese; f) obesity was absent among subjects with a peripheral pattern, except for one male showing an endomorphic-mesomorph somatotype; h) the obese showed extreme somatotypes with high endomorphy and mesomorphy, and minimal ectomorphy. © 1994 Wiley-Liss, Inc.