A study has looked for genetic variations in people of European descent to identify any genes associated with curly and straight hair. People of European descent have 45% straight hair, 40% wavy, and 15% naturally curly hair. Professor Martin and colleague Dr Sarah Medland have previously found there is up to a 90% chance of inheriting the curly hair trait. The scientists, from the Genetic Epidemiology Laboratory at the Queensland Institute of Medical Research (QIMR) in Brisbane identified the TCHH gene (trichohyalin) on chromosome one as the major gene controlling the curliness of hair. TCHH has been known for over twenty years to play a role in the development of hair follicles. It is expressed in the inner root sheath of developing hair follicles. Leader of the team, Professor Nick Martin said that variations in the gene determine how straight or curly the hair is, but more work is needed to determine the exact variant that influences curliness. Professor Martin said a variation that causes a change in an amino acid is the most likely contender. The study analyzed data collected from a 30-year study of 5000 twins of European ancestry.
Humans still evolving as our brains shrink