GabyThe human face can express a wide range of emotions, many of which would be impossible without eyebrows. Although scientists still do not know exactly how and why these two small strips of dense (and in some cases, not so dense) hair appeared in humans. However, European researchers have now identified the genes that determine the spectrum of eyebrow shapes – from thick and wide to thin. It turns out that many of these genes are common among people worldwide.
Useful, yet very mysterious.
Eyebrows prevent sweat and light from entering the eyes and allow a person to express their emotional state. Depending on their size and shape, they can even enhance the attractiveness of their owner in the eyes of others. Therefore, it is not surprising that scientists have been pondering for quite some time whether the shape and thickness of human eyebrows are influenced by natural or sexual selection.
Until now, there has been very little data on the genetic factors that determine the appearance of eyebrows. As molecular biologist Manfred Kaiser from the Netherlands notes, despite the enormous efforts to map the genes underlying complex human traits, we still know more about the genes that make people sick than about those associated with a healthy appearance.
For this reason, the researcher believes that the new study significantly enhances genetic knowledge about the appearance of human eyebrows. Currently, the number of known genes in this area has increased from four to seven, creating new targets for future functional research.
Eyebrows are not only related to appearance.
Previously, scientists studied the genetics of eyebrow thickness in people of Latin American or Chinese descent. The new research is the first to also include Europeans. It involved 9,948 individuals who were divided into four different groups based on ancestral lines, including those from Europe, the United States, Australia, and the United Kingdom.
Researchers have identified three genes (SOX11, MRPS22, SLC39A12) that were previously unreported and are associated with eyebrow thickness only in Europeans. They also recognized two other genes (SOX2, FOXD1) that were found in previous studies of non-European individuals. Additionally, two genes (EDAR, FOXL2) identified in non-Europeans had no significant impact on the inhabitants of the European continent.
Mr. Kaiser points out that according to a new study, eyebrow variation is determined by both shared and distinct genetic factors in people across different continents. This means that the results highlight the need to study populations of different ancestors to uncover the genetic basis of human traits, including appearance, but not limited to it.
The first step to the path to further study
It is known that the thickness of a person’s eyebrows is an inherited trait. However, previous research on evolution in this area suggests that the genes SOX2, FOXD1, and EDAR are not subject to significant selection pressure.
This could mean that the thickness of a person’s eyebrows is not related to evolution for survival or sexual selection. It is a “neutral trait,” “without a visible connection to individual fitness” or attractiveness.
As noted by the publication Sciencealert This is an exciting discovery, especially considering how beneficial eyebrows are for humans. However, there is a possibility that scientists are simply not studying the right genes.
The latest identified “eyebrow genes” still require research to determine signs of natural or sexual selection. There is also a possibility that this will allow scientists to explain why humans developed such thick features above their eyes in the first place.
