Scientists Find Relationship Between Shape of Nose and Climate Change
Your local climate, not genetics, has shaped your nose. According to a study published on March 16 in the journal PLOS Genetics, people residing in a place with warm and humid conditions commonly have wider noses while those that live in cold and dry locations have narrower noses.
Mark Shriver, a geneticist and anthropologist at Pennsylvania State University, together with his team of international researchers from the U.S., Ireland and Belgium, measured and compared noses across populations using 3D facial imaging.
The study is not the first one to identify the relationship between nose shape and air temperature and moisture content. However, it is the first one to use nose measurement from actual people.
"Many people have tested the question with measurements of the skull, but no one had done measurements on live people," said lead author,Mark Shriver from Pennsylvania State University.
As reported by Science Recorder, all in all, faces of 476 from four geographical locations -- West Africa, East Asia, South Asia and Northern Europe -- were used in the study. Their ancestry though genetic measurement were also taken into consideration.
The researchers concluded that while the differences in nose shape was indeed influenced by genetic drift (the change in frequency of certain genes due to deaths and movement of people across borders), natural selection also played its role.
Narrower nasal passages assist in increasing the moisture content of air and warm it. Since people with narrower nasal adopted better, they survived more and therefore produced more offspring. As such, there is a gradual decrease in people with wider nose in the area.
Shriver said that this all points out to Thomson's Rule conceived by anatomist Arthur Thomson.
"In the late 1800s he said that long and thin noses occurred in dry, cold areas, while short and wide noses occurred in hot, humid areas. Many people have tested the question with measurements of the skull, but no one had done measurements on live people," Thomson told Science Daily.
In addition, along with selection based on climate, sexual selection also played a major role in shaping the nose, as people are likely to choose mates based on their concept of "beauty."