Heritability of face shape in twins: a preliminary study using 3D stereophotogrammetry and geometric morphometrics

Abstract

Introduction Previous research suggests that aspects of facial surface morphology are heritable. Traditionally, heritability studies have used a limited set of linear distances to quantify facial morphology and often employ statistical methods poorly designed to deal with biological shape. In this preliminary report, we use a combination of 3D photogrammetry and landmark-based morphometrics to explore which aspects of face shape show the strongest evidence of heritability in a sample of twins. Methods 3D surface images were obtained from 21 twin pairs (10 monozygotic, 11 same-sex dizygotic). Thirteen 3D landmarks were collected from each facial surface and their coordinates subjected to geometric morphometric analysis. This involved superimposing the individual landmark configurations and then subjecting the resulting shape coordinates to a principal components analysis. The resulting PC scores were then used to calculate rough narrow-sense heritability estimates. Results Three principal components displayed evidence of moderate to high heritability and were associated with variation in the breadth of orbital and nasal structures, upper lip height and projection, and the vertical and forward projection of the root of the nose due to variation in the position of nasion. Conclusions Aspects of facial shape, primarily related to variation in length and breadth of central midfacial structures, were shown to demonstrate evidence of strong heritability. An improved understanding of which facial features are under strong genetic control is an important step in the identification of specific genes that underlie normal facial variation.

Toward DNA-based facial composites: Preliminary results and validation

“…In addition to poor predictive capabilities, another shortcoming is that these measurements, even when several of them are used individually, still oversimplify the spatial configuration too much and when they are used together, they are difficult to interpret, as in they fail to produce an image-like overview of the result, which is needed to construct a facial composite. Alternatively, a dimensionality reduction technique, like principal component analysis (PCA) on landmark configurations or Fourier analysis on outline data, can be applied resulting in principal component (PC) axes [16,42] or harmonics [43], respectively. These values are then treated as separate morphological traits.…”

“…In theory, a DNA-based facial composite should be possible given the compelling evidence that facial features are under strong genetic control [15]. Such evidence includes remarkable facial similarity between identical twins [16], clear facial resemblances within families, distinctive facial features associated with particular genetic conditions [17,18], and facial similarities within geographic populations [19] and within the sexes [20]. This suggests that inter-individual variation in facial morphology is, in most cases, primarily determined by genetic variation.…”

The self prefers itself? Self-referential versus parental standards in face attractiveness

“…Given that phenotypic facial characteristics are known to be highly heritable in humans (Baydas et al, 2007; Weinberg et al, 2013), faces may be one of the best visual clues to genetic similarity (Kazem & Widdig, 2013; Holmes, 2004; Bovet et al, 2012). Indeed, for both sexes, ratings of facial attractiveness have been found to be a better predictor of general physical attractiveness than ratings on body images (Currie & Little, 2009; Peters, Rhodes & Simmons, 2007).…”

Exploring the Underlying Genetics of Craniofacial Morphology through Various Sources of Knowledge

“…Twin and other family studies of craniofacial shape show a moderate to high degree of heritability for a substantial set of craniofacial traits [46, 49–51]. Facial height, width, and nasal features, in particular, are more genetically determined than is facial depth [51].…”