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hair, eyebrows and beards

The gray hair gene

TecnocienciaDANIEL BUENOAn analysis of the DNA of 6,357 Brazilians, Colombians, Chileans, Peruvians and Mexicans provided important clues about the influence of certain segments of the human genome on the color, shape and absence of hair, as well as some characteristics of eyebrows and beards (Nature Communications, March 1, 2016). Eighteen associations were identified between genes and the physical traits of the participants in the study, coordinated by researchers from the University College London. According to the authors, 10 of these associations are new discoveries. Two of them are particularly worthy of note: the role of the IRF4 gene (located in chromosome 6) in hair color loss and the effect of a mutation in the PAX3 gene (chromosome 2) on eyebrow shape. IRF4 participates in the control of the production and storage of melanin, the dark pigment found in skin and hair. In the case of PAX3, the article shows that a variant of the gene is why some people have what is popularly called a “unibrow”, i.e., eyebrows joined in a continuous line. The study was performed on Latin Americans due to their wide genetic variability and hair characteristics. The Brazilian part of the study was conducted by the research group led by Professors Francisco Salzano and Maria-Cátira Bortolini of the Federal University of Rio Grande do Sul (UFRGS).