Human Facial Shape and Size Heritability and Genetic Correlations

Abstract

The human face is an array of variable physical features that together make each of us unique and distinguishable. Striking familial facial similarities underscore a genetic component, but little is known of the genes that underlie facial shape differences. Numerous studies have estimated facial shape heritability using various methods. Here, we used advanced three-dimensional imaging technology and quantitative human genetics analysis to estimate narrow-sense heritability, heritability explained by common genetic variation, and pairwise genetic correlations of 38 measures of facial shape and size in normal African Bantu children from Tanzania. Specifically, we fit a linear mixed model of genetic relatedness between close and distant relatives to jointly estimate variance components that correspond to heritability explained by genome-wide common genetic variation and variance explained by uncaptured genetic variation, the sum representing total narrow-sense heritability. Our significant estimates for narrow-sense heritability of specific facial traits range from 28 to 67%, with horizontal measures being slightly more heritable than vertical or depth measures. Furthermore, for over half of facial traits, .90% of narrow-sense heritability can be explained by common genetic variation. We also find high absolute genetic correlation between most traits, indicating large overlap in underlying genetic loci. Not surprisingly, traits measured in the same physical orientation (i.e., both horizontal or both vertical) have high positive genetic correlations, whereas traits in opposite orientations have high negative correlations. The complex genetic architecture of facial shape informs our understanding of the intricate relationships among different facial features as well as overall facial development.

Genome-wide Association study of facial morphology identifies novel genetic loci in Han Chinese

“…Lee et al identified two genetic variants of FREM1 and PARK2 associated with face shape in individuals of European ancestry (Lee et al, 2017). In 2018, two studies (Claes et al, 2018;Crouch et al, 2018) found a number of newly associated genetic loci by applying novel approaches to a European-derived cohort and replicated many loci in previous studies Paternoster et al, 2012;Adhikari et al, 2016;Shaffer et al, 2016). In African subjects, SCHIP1 and PDE8A were identified to be associated with measures of human facial size (Cole et al, 2017).…”

Hunting for genes that shape human faces: Initial successes and challenges for the future

“…Since the 1950s, numerous studies have attempted to estimate the heritability of simple anthropometric or cephalometric measurements of the craniofacial complex . Some more recent studies with access to large 3D facial data sets have employed more advanced morphometric methods in an effort to better quantify complex aspects of soft‐tissue facial morphology . Collectively, these studies report a wide range of heritability estimates, even when the same measurement is considered, making generalizations difficult.…”

“…[6][7][8] Some more recent studies with access to large 3D facial data sets have employed more advanced morphometric methods in an effort to better quantify complex aspects of soft-tissue facial morphology. 9,10 Collectively, these studies report a wide range of heritability estimates, even when the same measurement is considered, making generalizations difficult. However, virtually all of these studies report high heritability (h 2 > 60%) for at least a subset of facial traits, with the majority of traits typically falling in the moderate heritability range.…”

Craniofacial skeleton of MEXICAN tetra (Astyanax mexicanus): As a bone disease model

“…These include cleft lip and palate; small or absent facial and skull bones; inappropriate nose, eyes, and ears; and abnormal dentition (Trainor, ; Trainor and Andrews, ). The craniofacial skeleton is a complex trait and the full spectrum of genetic and environmental factors that contribute to its final structure remains largely unknown (Hallgrimsson et al, ; Powder and Albertson, ; Cole et al, ). Similarly, majority of the craniofacial structural birth defects have multifactorial etiology (Young et al, ; Manyama et al, ; Marcucio et al, ; Cole et al, ).…”

“…The craniofacial skeleton is a complex trait and the full spectrum of genetic and environmental factors that contribute to its final structure remains largely unknown (Hallgrimsson et al, ; Powder and Albertson, ; Cole et al, ). Similarly, majority of the craniofacial structural birth defects have multifactorial etiology (Young et al, ; Manyama et al, ; Marcucio et al, ; Cole et al, ). The externally developing, transparent teleost embryos are excellent models to study the early events of head formation.…”