Have you ever wondered why you have hair in the legs but not in the plants at your feet?
Or why we have a lot of hair in the head, but not a single hair in the palms of our hands?
The issue has been for years a pending issue for doctors, researchers and other scholars of the complex machinery of the human body.
For decades, science has been limited to considering it to be one evolutionary trait of some animals, but the physiological explanation of how it was produced was until recently a question.
Scientists at the Faculty of Medicine at the University of Pennsylvania have investigated this "mystery" for years and now claim that they had an answer.
The study, published in the magazine Reports of cells, indicates that "or guilty" of no We get hair in certain areas of our body is a special type of molecule, for more signal, a protein.
According to the researchers, it deals Dickkopf 2 (DKK2), which blocks the so-called "WNT signaling paths", mobile channels that, among other things, are responsible for triggering hair growth.
"In this study, we show that skin in regions without hair naturally produces an inhibitor that prevents WNT from doing its work," he told the magazine. Newsweek Sarah E. Millar, one of the authors of the investigation.
"We know that the signaling of WNT is essential for the development of hair follicles, the blockage causes a skin without skin and the activation causes the formation of more hair," he said.
But why do some animals have hair in most of their body and others do not?
The study suggests that it is, as has been known for years, an evolutionary adaptation.
The investigation considers that certain animals have evolved to produce DKK2 in certain parts of their bodies It helps them to survive better to their environments.
Thus, for example, a hair-free hand would serve more to maintain instruments or other tasks, while the absence of hair on the feet would help you to walk better.
In cold climates, however, it would be better if they were coated, as in the case of polar bears.
To reach these conclusions, the team analyzed the skin of the legs of a mouse (which, like humans, has no hair on its plants) and compared it to other animals that do it, such as rabbits.
By comparing the DKK2 levels between the two species, they found that the amount of protein was markedly lower in the skin of animals that have hairs in the legs.
Meanwhile, the level of the molecule was much higher in areas where hair does not grow in the higher zones.
The study indicates that there is no signaling pathway WNT in these areas, hair generators, but that the protein blocks.
Now researchers hope that the discovery can be used for new research on hair growth, the treatment of some diseases or future treatments for people who have suffered severe burns or accidents.