The first "graying gene" has been discovered
An international team of researchers led by Dr. Kaustubh Adhikari from University College London has identified the first gene responsible for graying hair, which confirms at least partial genetic conditioning of this phenomenon.
As part of the study, scientists analyzed DNA samples from 6,630 volunteers living in Brazil, Colombia, Chile, Mexico and Peru. After the initial screening, 6,357 samples were accepted for work, 45% of which belonged to men and 55% to women. This group included people of mixed European (48%), Native American (56%) and African (6%) origin, which provided researchers with a wide range of variations in the characteristics of the scalp.
For all women and men, a description of the shape and color of hair, as well as the nature of baldness and graying, was compiled. For men, a description of the beard and eyebrows was also compiled (the density and presence of fused eyebrows). The visual characteristics of each participant were compared with the results of a genome-wide analysis of their DNA, which made it possible to identify the genes responsible for the differences in external signs.
After that, the data obtained were compared with existing databases for different populations in order to use the already available information to understand the patterns of selection of certain traits.
The most interesting result of the work done was the identification of the first known genetic association for graying hair. It turned out that the IRF4 gene, previously known as partially responsible for skin and hair color, is involved in hair discoloration. This gene is involved in the regulation of the production and storage of the enzyme melanin – the pigment responsible for the color of the skin, hair and eyes.
Hair graying is the result of a complete absence of melanin, so researchers want to find out the exact role of IRF4 in the development of this phenomenon. Understanding this mechanism will allow the development of new cosmetic preparations that change the appearance of hair by blocking or slowing down their graying at the level of hair follicles.
Another interesting finding was a previously unknown variation of the PRSS53 gene that affects the shape of the hair. The enzyme encoded by this gene – component 53 of the serine protease family S1 (Protease Serine S1 family member 53, PRSS53) – functions in the area of the hair follicle, where the shape of the growing hair is formed. The identified variation of this gene is associated with straight hair of people of East Asian origin and Native Americans, which confirms the hypothesis that this form of hair is a relatively recent result of human evolutionary selection.
The researchers also identified additional genes associated with hairline characteristics, including the EDAR gene responsible for the thickness and shape of beard hair, as well as the FOXL2 gene responsible for eyebrow density, and the PAX3 gene associated with fused eyebrows.
According to Dr. Adhikari, the results obtained can help in the development of forensic technologies for modeling visual signs based on a person's genetic profile. Earlier developments in this area used samples of people of European origin, while new results may help criminologists in Latin America and East Asia.
He also notes that experts have been discussing the hypothesis for a long time, according to which the characteristics of the hair cover are subjected to some form of selection, natural or sexual, while the data obtained provide statistical confirmation of this assumption. However, most likely the identified genes are responsible for graying or the shape of hair and eyebrows not alone, but in combination with many other factors that have yet to be identified.
Article by Kaustubh Adhikari et al. A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features published in the journal Nature Communications.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of University College London: First gene for grey hair found.