Climate may affect the shape of a person’s nose more than genetics, according to a new study published in the journal PLOS Genetics.
These new findings come from researchers at Penn State University, who found that nose shape appears to differ based on the region in which someone lives. For example, groups in warm, humid climates tend to have wider noses while those in cold or dry climates have narrow noses.
The team believes this could be tied to genetic drift, a process by which certain genes become more or less prevalent randomly throughout populations. This has played a big role in human evolution and often causes unique traits to arise. However, there is also a chance that nose shape is tied to natural selection.
Researchers used 3D facial imaging to analyze the noses of more than 2,600 participants from West Africa, South Asia, East Asia, and Northern Europe. This allowed them to look at numerous measurements, including nostril width, nose height, the distance between nostrils, ridge length, and nostril area. They estimated each subject’s ancestry through genetic testing as well.
“We are interested in recent human evolution and what explains the evident variation in things like skin color, hair color and the face itself,” said study co-author Mark D. Shriver, a professor of anthropology at Penn State University, in a statement. “We focused on nose traits that differ across populations and looked at geographical variation with respect to temperature and humidity.”
The tests revealed that two distinct nose measurements — nostril width and the width of the nose at its base — seem to be directly connected to climate. People with wider nostrils are more likely to live in hot, humid climates and people with narrower nostrils are more likely to live in cold, dry climates.
While the nose is mainly used for smelling and breathing, it also helps to warm and moisten air before it enters the lungs, Live Science reports. As a result, hot air does change much as it moves through the nostrils. However, cool air must be warmed up before it gets into the body. Narrow nostrils may help with this process by forcing air to come into contact with warm mucus in the nose.
The research gives new insight into nose shape and could provide clues about human evolution. The information also could be important from a medical standpoint, especially as more and more people travel across the world. This is because it may allow doctors to better diagnose patients and understand that if someone has a narrow nose, they could be at risk for respiratory problems in certain parts of the world.
The team plans to continue their study and look at people living in high altitudes to see if oxygen levels affect nose shape as well.
“[T]hese traits are important to study because they are likely tied to our health, especially as we become more of a global community and migrate to new climates,” added lead author Arslan A. Zaidi, a researcher at Penn State University, in another statement.