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

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

Patellar tendon lengthening: rescue procedure for patella baja

Patella baja is a challenging pathologic condition that causes pain and functional restrictions and can even lead to premature osteoarthritis-even more so in cases of patella infera or cases associated with degeneration of the patellar tendon in which simple conservative treatment frequently is not resolutive. Several surgical options have been described for symptomatic patella baja: excision of the lower third of the patella, lengthening of the patellar tendon, reconstruction of the patellar tendon with allograft, and proximalization of the tibial tubercle. A combination of 2 or more of these treatments may be recommended in cases of significant patella baja. We present a simple and reproducible technique to address patella baja that combines a partial transposition of the tibial tubercle and patellar tendon lengthening using a subperiosteal patellar flap in continuity with the patellar tendon

Patellar Tendon Lengthening: Rescue Procedure for Patella Baja

Patella baja is a challenging pathologic condition that causes pain and functional restrictions and can even lead to premature osteoarthritis—even more so in cases of patella infera or cases associated with degeneration of the patellar tendon in which simple conservative treatment frequently is not resolutive. Several surgical options have been described for symptomatic patella baja: excision of the lower third of the patella, lengthening of the patellar tendon, reconstruction of the patellar tendon with allograft, and proximalization of the tibial tubercle. A combination of 2 or more of these treatments may be recommended in cases of significant patella baja. We present a simple and reproducible technique to address patella baja that combines a partial transposition of the tibial tubercle and patellar tendon lengthening using a subperiosteal patellar flap in continuity with the patellar tendon

Effects of hormonal treatment, maxilofacial surgeryorthodontics, traumatism, and malformation on fluctuating asymmetry

En este trabajo se evalúa la relación entre la asimetría fluctuante facial (AFF) y los tratamientos hormonales, cirugías maxilofaciales, ortodoncia, traumatismos y malformaciones. En el marco del proyecto CANDELA, se tomaron cinco fotografías faciales de 3162 voluntarios entre los 18 y 85 años. Por fotogrametría se colocaron 34 landmarks o puntos en 3D y mediante el método Procrustes ANOVA se obtuvieron valores individuales de asimetría fluctuante facial. Se realizó una prueba de ANOVA de una vía y la prueba de Welch y Levene para conocer las diferencias entre media y varianza de los valores de asimetría facial y las variables respuesta. También, se caracterizó la variación morfológica del componente asimétrico de la forma facial mediante técnicas multivariadas sobre los grupos que resultaran diferentes significativamente. Las mujeres que reportaron haber recibido algún tipo de tratamiento hormonal mostraron mayores valores de asimetría fluctuante facial respecto al grupo sin tratamiento. Esta asociación se mantuvo una vez removido el efecto de la heterocigosidad (como indicador de la ancestría) y sin interactuar con el resto de covariables incluidas en el análisis. Los cambios morfológicos asociados a este factor se concentran en el mentón, maxilar labio inferior, región perifrontal, región nasal y orejas. Algunos trabajos anteriores dieron cuenta de la posible relación entre la asimetría facial y los niveles de hormonas, pero no hay estudios que sustenten la relación causal o directa entre la asociación aquí planteada. El presente trabajo es una evidencia más de la asociación entre el consumo de hormonas y modificaciones de caracteres faciales en poblaciones urbanas mestizas latinoamericanas.In this work we test for the putative association between facial fluctuating asymmetry (FFA) and hormone treatments, maxillofacial surgery, orthodontics, injuries, and malformations. A protocol of five photographs and photogrammetric reconstruction was implemented to place thirty-four 3D landmarks in 3162 individuals aged between 18 and 85 years, belonging to the CANDELA initiative. A Procrustes ANOVA test was used to obtain individual facial fluctuating asymmetry scores. One way ANOVA, Welch, and Levene tests were conducted to explore the potential differences between mean and variance of the response variables. Our results indicate that women who received some hormonal treatment showed higher fluctuating facial asymmetry scores in relation to the unaffected group, this being persistent once the effects of heterozygosity (genetic ancestry) and further variables had been statistically controlled. The shape changes corresponding to this association are focused on the chin, jaw, lower lip, prefrontal region, nose, and ears. Previous reports suggested a potential relationship between facial asymmetry and hormone levels, but to the best of our knowledge there are no reports indicating the causation underlying the association detected here. This report is one more evidence of the association between hormone intake and facial asymmetric features in urban admixed Latin American populations.Asociación de Antropología Biológica de la República Argentin

Relación entre tratamiento hormonal, cirugía-ortodoncia maxilofacial, traumatismos y malformaciones craneofaciales y la asimetría fluctuante

En este trabajo se evalúa la relación entre la asimetría fluctuante facial (AFF) y los tratamientos hormonales, cirugías maxilofaciales, ortodoncia, traumatismos y malformaciones. En el marco del proyecto CANDELA, se tomaron cinco fotografías faciales de 3162 voluntarios entre los 18 y 85 años. Por fotogrametría se colocaron 34 landmarks o puntos en 3D y mediante el método Procrustes ANOVA se obtuvieron valores individuales de asimetría fluctuante facial. Se realizó una prueba de ANOVA de una vía y la prueba de Welch y Levene para conocer las diferencias entre media y varianza de los valores de asimetría facial y las variables respuesta. También, se caracterizó la variación morfológica del componente asimétrico de la forma facial mediante técnicas multivariadas sobre los grupos que resultaran diferentes significativamente. Las mujeres que reportaron haber recibido algún tipo de tratamiento hormonal mostraron mayores valores de asimetría fluctuante facial respecto al grupo sin tratamiento. Esta asociación se mantuvo una vez removido el efecto de la ancestría genética y sin interactuar con el resto de variables incluidas en el análisis. Los cambios morfológicos asociados a este factor se concentran en el mentón, maxilar labio inferior, región perifrontal, región nasal y orejas. Algunos trabajos anteriores dieron cuenta de la posible relación entre la asimetría facial y los niveles de hormonas, pero no hay estudios que sustenten la relación causal o directa entre la asociación aquí planteada. El presente trabajo es una evidencia más de la asociación entre el consumo de hormonas y modificaciones de caracteres faciales en para poblaciones urbanas mestizas latinoamericanas

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.]

Results of HLM for FFA scores against age, sex, BMI, genetic ancestry and PC scores for wealth index.

<p>For simplicity, and considering the high correlation between both data sets, results are presented only for heterozygosity-corrected data (blue-colored cells indicate significant effects at p< = 0.01).</p