Various features relating to facial size and shape are obviously genetic—it’s why people in the same family can look alike, for instance—but only a small number of genes are known to actually influence facial shape and development.
This number may, however, have gone up, according to some findings out of the Colorado School of Medicine.
Two genes have been identified that the researchers believe could be significant players in human facial development and 10 other genes are being suspected as candidates as well.
The researchers looked at 3,505 African Bantu children and young adults (ages 3 to 21) from the Mwanza region of Tanzania. This group was selected because the population is very lean and the Mwanza area has a fairly constant climate.
This helped minimize the potential influence of body fat and environmental influences on facial development. Genetic tests were performed and facial scans were taken and tracked. It was found that the expression of two genes, SCHIP1 and PDE8A, were strongly associated with certain facial size measurements.
In order to confirm that these genes did play a role in facial development, the scientists raised mice with the genes turned off. When SCHIP1 was deactivated, the mice had abnormal development along the palate, neural crest, and snout. PDE8A didn’t seem to influence facial development in the mice, but the correlation in the human participants was strong enough that the researchers theorized the gene influenced developmental traits that didn’t come into play until after birth.
What This Means
Since past findings suggest that genes connected to facial development in one ethnicity do not always have the same influence in another, it’s important to keep in mind that these findings primarily relate to African individuals. If the involvement of SCHIP1 and PDE8A is confirmed, then it will be a useful contribution to understanding facial genetics and further research could be done to see if these genes have more specific relations to various features, like how far apart the eyes and nose are.
On a more practical level, understanding facial genes and how they affect the size and shape of the face could have implications for treating craniofacial syndromes like cleft palate. Getting more specific on this matter will require further research, however, as would determining any potential benefits for fields like facial remodeling or forensics.
Cole, J., et al., “Genomewide Association Study of African Children Identifies Association of SCHIP1 and PDE8A with Facial Size and Shape,” PLOS Genetics, 2016; http://dx.doi.org/10.1371/journal.pgen.1006174.