A new study led by researchers from Pennsylvania State University suggests that we should not blame our parents for the size and shape of our nose. Instead, it appears to have evolved according to the local climate conditions.
The nose is probably the most distinctive feature on our faces and plays an important role, as it is responsible with conditioning the air we breathe. However, not all noses look the same. Scientists usually accounted for these differences in shape and size on the basis of genetic drift, a random process that occurred among the human population.
Is genetic drift responsible for all these variations?
Researchers discovered that nose shapes were pretty varied. They suggested that genetic drift alone could not account for so many differences in nostril and nose base width. Thus, they suspected that natural selection must have played an important role in determining the nose shape in humans.
Therefore, the local climate must be, in part, responsible with the evolution of the nose shape. To prove this hypothesis, researchers developed a study where they looked at nose traits which differ among various populations and then looked at the temperature and humidity conditions in each geographical area.
Wider nostrils are more common in hotter climates
Results showed that nose shape is indeed related to the climate conditions of the area where humans live. Nostrils differ in width according to variations in temperature and humidity. Mark D. Shriver, professor at Pennsylvania State University, offered a brief explanation of their results.
“The positive direction of the effects indicate that wider noses are more common in warm-humid climates, while narrower noses are more common in cold-dry climates.”
Why do temperature and humidity influence the nose shape?
One of the main roles of the nose is to make sure that the air it inhales is warm and moist. A narrower nostril can manipulate the air better. Thus, the mucous membrane can warm the air up more effectively and make it moister. This is why people from colder climates have narrower nostrils. They probably helped them cope better with the harsh conditions.
Therefore, these temperature and humidity conditions led to a gradual decrease in the size of the nostrils in people living further away from the equator. This study suggests that genetics is not always responsible for certain traits in our appearance. If you wanted to give the study a closer look, it was published in the journal PLOS Genetics.
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