Eyebrow Thickness? It’s in Your Genes
The first gene mapping study on eyebrow thickness in Europeans discovered three previously unreported genetic loci, suggesting that eyebrow appearance has partly the same and partly different underlying genes in people from different parts of the world.
The study, conducted by the International Visible Trait Genetics (VisiGen) Consortium, is published as a Letter to the Editor in the Journal of Investigative Dermatology.
Thus far, genetic knowledge on eyebrow thickness has been very limited and solely restricted to non-Europeans. This study is the first genome-wide association study (GWAS) on eyebrow thickness in Europeans.
Previous studies were performed among Latin American and Chinese individuals, establishing four eyebrow thickness-associated genetic loci. Because no European eyebrow thickness GWAS had been reported, researchers did not know whether the genetic eyebrow thickness effects described in non-Europeans persist in Europeans, or whether there are European-specific genetic loci involved in eyebrow thickness, or both.
“For the first time, we performed a gene mapping study on eyebrow thickness variation in Europeans,” says Prof. Dr. Manfred Kayser, Department of Genetic Identification, Erasmus MC University Medical Center Rotterdam, and co-chair of the VisiGen Consortium, in a news release. “We discovered new genes involved in eyebrow variation in Europeans and rediscovered some of the genes previously identified in non-Europeans."
The study included 9,948 individuals from four groups of European ancestry not only discovered three previously unreported genetic loci associated with eyebrow thickness, but also rediscovered two of the four genetic loci previously found in non-Europeans. Two other genetic loci previously reported in non-Europeans had minimal effects in Europeans, due to very low allele frequencies in Europeans.
"Our study significantly improves the genetic knowledge of human eyebrow appearance by increasing the number of known genes from four to seven and delivers new targets for future functional studies,” says Dr. Kayser. “By having demonstrated that eyebrow variation is determined by both shared and distinct genetic factors across continental populations, our findings underline the need for studying populations of different ancestries for unveiling the genetic basis of human traits, including, but not restricted to, physical appearance."