However, people's definition of a beautiful nose is changeable and sometimes even biased. For example, in early Europe, aquiline nose meant beauty and nobility. The Nazis looked down on this shape of nose and thought it was characteristic of Jews. More biased, Jews are often described as aquiline noses to show their evil. Shakespeare's Sherlock is an example.
However, in all these fickle pseudosciences, some biological facts and problems are still unclear. For example, why are there such racial differences in the shape of people's noses? We answered this question by identifying some genes related to the shape of the nose, and the research results were also published in the journal Nature Communication.
Evolutionary origin
Evolutionary scientists believe that the nose is the result of human adaptation to climate changes when moving from Africa to colder regions. This is the first time that scientists have clarified this problem. They believe that the narrow nose of Europeans today mainly evolved because the nose gradually adapted to the dry and cold climate, so that cold air can be preheated and humidified in the nasal passages before reaching the lungs. Similarly, scientists interpret the wide and flat noses of East Asians and Siberia (ancestors of Indians) as an adaptation to the climate, so that they can minimize heat loss in cold environments.
Since natural selection only works at the genetic level, this leads to the next obvious question: what genes cause these changes in the nose? This question is difficult to answer. People have found some mutations that cause skull and facial deformities in humans and other animals, but we still don't know which genes regulate normal facial changes.
Part of the reason why this problem is difficult to solve is that most studies are limited to a mainland population-Europeans. These studies have an inherent limitation, because if almost everyone in that population has a unique feature, then these features will not change, even if that feature is obviously different from other mainland populations, it is impossible to make statistical analysis.
Image source: provided by the author
We used a large Latin American data set named Candela Group, which collected data from five countries from Mexico to Chile. This reflects the great differences in ancestors, geography and environment between the mainland and the subcontinent. Because Latin Americans are a mixture of Europeans, Indians and Africans, they provide great genetic diversity for our research. Previously, we used this group to find genes related to the changes of ear shape and hair characteristics for the first time.
In this new study, we observed thousands of people in the data set and detected common genetic variations to find the variations associated with specific nose types. Our two colleagues, Macarena Fuentes-Guajardo from University College London and Mirsha Quinto-Sanchez from the National Center of Patagonia, Argentina, described the facial changes of the participants by analyzing their facial photos in 2D and 3D. Let's start with the general features of about 6000 people (such as wide/average/narrow nose), and then further quantify the nose features more accurately through 3D analysis of about 3000 people.
Known gene
The upper part of our nose is made up of bones, while the lower part is made up of cartilage. We found that the width of the bridge of the nose (the end of the bony part of the nose) is related to RUNX2 gene, and run x2 gene is related to bone development. So if your nose is wide, you may be carrying some form of RUNX2.
In addition, the width of alar (the width between nostrils) is related to GLI3 and PAX 1 genes. At the same time, various characteristics of nose sharpness (such as nose protruding length, nose inclination and tip angle) are related to DCHS2, and dch S2 is involved in cartilage growth. It has been found that all these genes are related to the development of bone or cartilage, and a few mutants of these genes are related to skull and facial deformities of people or other animals. However, it is not until now that we know that they actually play a role in normal facial changes.
How do we relate genes to the shape of the nose? Image source: provided by the author
Our research results are not only of great significance to explain the differences of human nose shape between different continents, but also some identified genes related to nose shape can confirm our evolutionary history-the evolution of nose shape has led to the racial differences we are concerned about now, and the above genes can be used for the genetic basis research of nose shape evolution. Interestingly, it has been known that compared with early Homo sapiens such as Neanderthals and Denisova (whose noses are also slightly different), GLI3, DCHS2 and RUNX2 genes have undergone great changes in modern people, especially GLI3, which has undergone rapid evolution in modern people.