Although the rule is well-established, it was not clear whether the differences arose as a response to selection pressures, or whether it was simply due to genetic drift — chance mutations, conserved without any particular survival benefits. Researchers set out to uncover whether nose size evolved as an adaptation to climate. Once the 3-D data had been analyzed, the team concluded that the width of the nostrils and the base of nose measurements across these regions could not be explained by chance alone.
They also found that wider nostrils correlated with populations whose ancestors evolved in warmer, more humid regions. This suggests that climate was a driving factor in the evolution of nose shape. The theory is that narrower nostrils alter airflow in such a way that the mucus-covered nasal membrane can warm and humidify incoming air more efficiently.
This would help individuals with narrower noses to survive better in colder climes and, therefore, be more likely to reproduce. Over time, this would have slowly driven nose size down. Of course, climate is not the only factor that has had a large impact on the evolution of the nose.
For instance, cultural preferences for nose shape are thought to play a part. If a certain culture finds larger noses attractive, then individuals with genes that prescribe a larger nose are more likely to breed and spread their large nose genes to the next generation. This finding is in line with the consensus that most human variation is shared among populations and primarily due to genetic drift.
We found that the width of nose bridge—the endpoint of the bony part of our nose—is associated with the gene RUNX2 , which is known to be involved in bone development. So if you have a wide nose bridge, you may be carrying a certain version of this gene. In addition, nose wing breadth, the width of our nose across the nostrils, is associated with the genes GLI3 and PAX1.
Meanwhile, various nose pointiness traits such as nose protrusion, nose inclination, and nose tip angle are associated with DCHS2 , which is involved in cartilage growth. All of these genes were previously known to be involved in bone or cartilage development, and rare variants of them have been characterized with skull and face malformations in humans or other animals.
Our results are not only important for explaining the differences in nose shape between different continents. Some of the identified nose genes also corroborate our evolutionary history—providing the first steps towards a genetic basis of nose-shape evolution which led to the ethnic variation we notice today. This is particularly true for GLI3, which is undergoing rapid evolution in modern humans. By providing your email, you agree to the Quartz Privacy Policy.
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Inline Feedbacks. Preni Venessa. September 20, pm. November 1, pm. November 13, am. Adam Weishaupt. November 30, am. January 4, pm. This is ignorant. There is no normal! February 26, pm. Patrick Sandoval. February 28, am. Sara Lang. April 7, pm. Michelle Lucas. June 26, am. September 14, pm. She says Shriver's analysis of the soft nose tissues "better accounts for the underlying genetics and conducts a more thorough assessment of the potential influence of natural selection in shaping the nose.
However, Harvati notes that only nasal width appeared to correlate with climate, while other factors of the nose such as height or overall size measured by Shriver's team showed no relation. This suggests "that the overall shape of the nose is not related to climate, and is influenced by many other factors which are not necessarily under selection. He hopes that, eventually, it will also help people use DNA to reconstruct faces of long dead humans and human ancestors.
But his next step for the nose research is to look for the specific genes that cause these differences in nasal width between different human populations. Until then, breathe deep and enjoy the centuries of evolutionary work that has gone into making your nose the way it is. New research strengthens the theory that different climates influenced the shape of the human nose.
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