London: Curly hair has been a mystery scientists have long pondered, and so have the rest of us. However, recent research has helped to unravel the intricate biology that decides if it’s straight, wavy, or tightly coiled.
Hair follicles—these are tiny structures within the skin—are at the heart of this follicular phenomenon. Follicles are the architects of the shape of our hair: straight follicles form straight hair fibres, whereas curly follicles contain curly ones.
However, the exact mechanism by which these follicles take their shape during embryonic development is elusive to scientists. The hair follicles are typically S-shaped, curved with two bends that determine the course for the rest of life. 1 Unlike curly follicles, which curiously goose their curly shape consistently, which is due to the fact that hair that makes structural changes every few years always regenerates the shape, giving the curls another day to come next time.
Hair texture is heavily based on genetics. If one parent has curly hair, there is more chance for their offspring to have curly hair. This is because curly hair is dominant over straight hair.
According to Dr. Sarah Medland of the QIMR Genetic Epidemiology Laboratory: ‘In terms of your hair, variations in the trichohyalin gene will determine whether you are most likely to have straight, wavy, or curly hair.’. The gene is present in hair follicle sheath formation, in which its direct involvement in the determination of hair curliness is observed.
Follicle shape is not responsible for all hair curls. Cells divide and make certain proteins in the follicle asymmetrically, in accordance with the bends in curved follicles. The elongation of a hair fibre laterally to the axis of a bra is due to this asymmetry, so that the fibre becomes elliptical and can curl.
Curly hair may look good to most, but its maintenance is more demanding than even straight hair is. Curly hair has a very different structure than normal hair, with a greater chance of dryness and breakage, so unique care routines are needed.
While research continues, scientists are doing their best to systematically discover the full genetic and biological mechanism of hair texture. Such knowledge might allow us to devise new hair-related conditions, treatments, as well as beauty industry innovations.