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Accurate gathering of phenotypic information is a key aspect in several subject matters, including biometrics, biomedical analysis, forensics, and many other. Automatic identification of anatomical structures of biometric interest, such as fingerprints, iris patterns, or facial traits, are extensively used in applications like access control and anthropological research, all having in common the drawback of requiring intrusive means for acquiring the required information. In this regard, the ear structure has multiple advantages. Not only the ear's biometric markers can be easily captured from the distance with non intrusive methods, but also they experiment almost no changes over time, and are not influenced by facial expressions. Here we present a new method based on Geometric Morphometrics and Deep Learning for automatic ear detection and feature extraction in the form of landmarks. A convolutional neural network was trained with a set of manually landmarked examples. The network is able to provide morphometric landmarks on ears' images automatically, with a performance that matches human landmarking. The feasibility of using ear landmarks as feature vectors opens a novel spectrum of biometrics applications. [ABSTRACT FROM AUTHOR]

Recently, the improvement of methods for shape analysis has revolutionized the field of morphometrics. While three-dimensional (3D) imaging technology is increasingly available, many studies of 3D structures still use two-dimensional (2D) data, even when this may result in the loss of important information. This is particularly conspicuous in the study of small mammals, as devices precise enough for 3D digitization of small objects are the most expensive. Thus, the development of low-cost methods aimed to recover 3D shape from small mammals would be of wide interest. Photogrammetry allows for obtaining 3D data with a lower cost than other 3D techniques, but it has not been previously applied to the study of small mammals. Accordingly, here we test the suitability of photogrammetric techniques to obtain 3D landmarks on mouse skulls as a model for small mammals. Shape and size of 3D models obtained with photogrammetric techniques were consistent among replicates, even when different sets of photographs were used. The linear measurements obtained from 3D models produced here were highly correlated with measurements obtained with callipers on actual crania, and differences among both sets of measures were smaller than those among individuals in most of the tested measures. These results show for the first time that photogrammetry is a precise technique for 3D shape analysis of small mammals. Photogrammetry also proved to be accurate for obtaining linear measurements between 3D landmarks; however, further studies are needed to demonstrate that this technique is also accurate to recreate 3D shapes. [ABSTRACT FROM AUTHOR]

Objective Here we evaluate morphological integration patterns and magnitudes in different skull regions to detect if shifts in morphological integration are correlated to the appearance of more processed (softer) diets. Methods To do so, three transitional populations were analyzed, including samples from groups that inhabited the same geographical region and for which the evidence shows that major changes occurred in their subsistence mode. Ninety three-dimensional landmarks were digitized on 357 skulls and used as the raw data to develop geometric morphometric analyses. The landmark coordinates were divided into several different regions of biomechanical interest, following a three-level hierarchically nested scheme: the whole skull, further subdivided into neurocranium (divided into the vault and basicranium), the facial (divided into the lower and upper facial), and the masticatory apparatus (divided into alveolar, temporal, and temporo-mandibular joint). Results Our results indicate that the morphological integration and variability patterns significantly vary across skull regions but are maintained across the transitions. The alveolar border and the lower facial are the regions manifesting greater value of morphological integration and variability, while the upper facial, the temporo-mandibular joint, and the basicranium are highly integrated and poorly variable. Conclusions The transition to softer diets increased morphological variation across cranial regions that are more exposed to masticatory strains effects. Am. J. Hum. Biol. 28:118-128, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT 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. Am J Phys Anthropol 157:58-70, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives It has been postulated that symmetric faces are considered more attractive than asymmetric ones because symmetry may signal high quality due to developmental stability. However, other studies showed that both symmetric and slightly asymmetric faces are considered attractive. Here we aim to explore this discrepancy, beginning with the analysis of the normal prevalence of facial symmetry in a population as a necessary first step prior to any attractiveness assessment. Methods We collected facial landmarks from two-dimensional digital images of a sample of Mexican individuals (280 females and 285 males aged 18-68 years) that were analyzed using geometric morphometric methods. Then, we chose a subsample of 100 photographs (50 females and 50 males aged 18-27 years) selected to represent a broad range of asymmetrical variation, in order to evaluate attractiveness using a sex-opposite test. Finally, we analyzed the linear correlation between attractiveness and asymmetry. Results We found that every evaluated subject presents some degree of facial asymmetry, and that both fluctuating asymmetry and directional asymmetry were significant ( P < 0.0001) components of total facial asymmetry. Fluctuating asymmetry was slightly associated with age ( r = 0.0858, P = 0.0414) and there were no differences between geographical regions ( P = 0.413). Attractiveness was not correlated to levels of asymmetry in either sex (males: P = 0.0973; females P = 0.7415). Conclusions Asymmetry was a prevalent feature in the present sample, and preferences for symmetric faces were not operating in the studied population. Am. J. Hum. Biol. 27:387-396, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives The head can be used as a model to study complex phenotypes controlled simultaneously by morphological integration (MI) due to common factors, and modular patterns caused by local factors affecting the development and functional demands of specific structures. The fibroblast growth factor and receptor system (FGF/FGFR) participates in cell communication and pattern formation in osseous tissues, among others, and there is compelling evidence from mouse model studies suggesting a role of the FGF/FGFR pathway as a covariance-generating signaling process in head development. Here we use human data to test if specific genetic variants of another gene of this pathway, the FGFR1 gene, can be associated with differences in the integration of the head. Methods We explored whether and how three specific variants on FGFR1, previously associated with human cephalic index, influence the pattern and level of head integration of one Native American and one admixed group from Mexico. MI, measured as the intensity of covariation among head traits, was assessed using data from three-dimensional head landmark coordinates taken on 176 individuals. Results Individuals carrying the derived allele of the rs4647905:G>C polymorphism present significantly greater levels of head MI, especially in facial structures and on the shape space where the modular portion of the covariation is explicitly removed. Conclusions Since FGFR genes present nonconservative and tissue-specific splicing sites, they may have some effect on protein structure and performance likely involved in developmental processes responsible for the magnitude and pattern of MI in the human head. Am. J. Hum. Biol. 26:164-175, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]