Australian scientists have made an interesting discovery recently, when they have managed to pinpoint the gene that is mostly responsible for a person having curly or straight hair. The TCHH gene (trichohyalin), which is located on chromosome one, appears to be the determining factor, the science team, from the Queensland Institute of Medical Research (QIMR) Genetic Epidemiology Laboratory, announces. The investigation was led by Professor Nick Martin, PhysOrg
In the new investigation, the scientists looked only at people of European descent. They did a comparative analysis of their genes, in an attempt to isolate precisely which one of them was responsible for producing curly hair. From the people that were analyzed, 45 percent had straight hair, 40 percent had wavy hair, and only 15 percent had curly hair. In a previous study, conducted with colleague Dr. Sarah Medland, Martin found that there were around 90 percent chances that future generations would inherit curly hair in people of European descent.
TCHH was known to be involved in creating hair follicles for a long time, but this is the first piece of evidence to suggest another role as well. The gene is usually expressed in the inner root sheath, but the team found that one of its variants directly influenced the curliness. Martin admits that a lot more work is needed before the exact gene variant is detected. Details of the new study, entitled “Common Variants in the Trichohyalin Gene Are Associated with Straight Hair in Europeans,” appear in the November 5 online issue of the American Journal of Human Genetics.
Studies on the curliness and straightness of hair are not new. A number of investigations have been conducted on Asian people, with the last one taking place last year, in Japan. Scientists managed to determine that the genes FGFR2 and EDAR were involved in producing the straight, thick hair type common in Asian people. Geneticists say that the two series of genes involved in hair types have evolved separately in European and Asians, after the two population groups diverged evolutionarily.