Genes for nose shape identified
Genes that drive the shape of human noses have been identified by a University College of London (UCL) study. These four genes affect the width and 'pointiness' of noses which vary greatly between different populations.
This new information helps explain how the human face evolved and may help contribute to forensic DNA technology in rebuilding visual profiles based on an individual's genetic makeup.
The study, published in Nature Communications, analysed a population of over 6,000 people with varied ancestry across Latin America. It studied the differences in normal facial features and identified genes which control the shape of the nose and chin.
Researchers identified five genes which play a role in controlling the shape of specific facial features. DCHS2, RUNX2, GLI3 and PAX1 affect the width and pointiness of the nose, while another gene — EDAR — affects how much the chin protrudes.
"Few studies have looked at how normal facial features develop, or only looked at European populations, which show less diversity than the group we studied. We found specific genes which influence the shape and size of individual features, which hasn't been seen before.
"Finding the role each gene plays helps us piece together the evolutionary path from Neanderthal to modern human. It brings us closer to understanding how genes influence the way we look, important for forensics applications."
Dr Kaustubh Adhikari, UCL Cell & Developmental Biology and first author of the report.
People have different shaped facial features based on their genetic heritage and this is partly due to how the environment influenced the evolution of the human genome. The nose, for example, is important for regulating the temperature and humidity of the air we breathe in so developed different shapes in warmer and cooler climates.
"It has long been speculated that the shape of the nose reflects the environment in which humans evolved. For example, the comparatively narrower nose of Europeans has been proposed to represent an adaptation to a cold, dry climate.
"Identifying genes affecting nose shape provides us with new tools to examine this relationship, as well as the evolution of the face in other species. It may also help us understand what goes wrong in genetic disorders involving facial abnormalities."
Andrés Ruiz-Linares PhD, Professor, UCL Biosciences, leader of the study.
The team collected and analysed DNA samples from 6,630 volunteers from the CANDELA cohort recruited in Brazil, Colombia, Chile, Mexico and Peru. After an initial screen, a sample size of 5,958 was used. This group included individuals of mixed European (50%), Native American (45%) and African (5%) ancestry, resulting in a large variation in facial features.
Both men and women were assessed for 14 different facial features and whole genome analysis identified the genes driving differences in appearance.
A subgroup of 3,000 individuals had their features assessed using a 3D reconstruction of the face in order to obtain exact measurements of facial features and the results identified the same genes.
The study identified genes involved in bone and cartilage growth and the development of the face:
GLI3, DCHS2, PAX1 all drive cartilage growth
• GLI3 - strongest signal for breadth of nostrils
• PAX1 also influences nostril breadth
• DCHS2 was found to control nose 'pointiness'
RUNX2 drives bone growth, width of nose bridge
The genes GLI3, DCHS2 and RUNX2 show strong signals of recent selection in modern humans when compared to archaic Neanderthals and Denisovans.
GLI3 in particular undergoes rapid evolution.
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.
Other authors: Kaustubh Adhikari, Macarena Fuentes-Guajardo, Mirsha Quinto-Sánchez, Javier Mendoza-Revilla, Juan Camilo Chacón-Duque, Victor Acuña-Alonzo, Claudia Jaramillo, William Arias, Rodrigo Barquera Lozano, Gastón Macín Pérez, Jorge Gómez-Valdés, Hugo Villamil-Ramírez, Tábita Hunemeier, Virginia Ramallo, Caio C. Silva de Cerqueira, Malena Hurtado, Valeria Villegas, Vanessa Granja, Carla Gallo, Giovanni Poletti, Lavinia Schuler-Faccini, Francisco M. Salzano, Maria- Cátira Bortolini, Samuel Canizales-Quinteros, Michael Cheeseman, Javier Rosique, Gabriel Bedoya, Francisco Rothhammer, Denis Headon, Rolando González-José, David Balding & Andrés Ruiz-Linares
UCL's contribution to this work was kindly funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
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For convenience, we summarized results across traits on a single ‘composite’ Manhattan plot
at the bottom of the figure (ordinal traits on the left and quantitative traits on the right).
These genes are connected with the list of associated facial features via lines of different colors.
The location of these features is illustrated on the face drawings shown at the top of the figure.
Image Credit: Emiliano Bellini, UCL Cell & Developmental Biology