Envious of another's natural curls? Don't be, researchers advise. Because it all comes down to the genes.
Professor Nick Martin and Dr Sarah Medland from the Queensland Institute of Medical Research (QIMR) have discovered trichohyalin gene that plays a vital role in development of the hair follicle.
They said that it is variation in this gene that determines the straightness or curliness of hair.
A group of Japanese researchers had previously found the genetic variations for the thick, straight hair that is predominant in Asian populations.
The differences in the EDAR and FGFR2 genes were identified last year and are thought to have occurred as part of the evolution of Asian populations following their prehistoric divergence from Europeans.
In the new study, the research team sought to determine a similar variation responsible for curly hair in those of European descent.
It is known that 45pct of European people have straight hair, 40pct have wavy hair and 15pct have curly hair.
They analysed data collected from a study of 5000 twins in Australia over a 30-year period. The twins had previously been asked if their hair was straight, wavy or curly and the lab then sought to match the reports with the 2.5 million single-nucleotide polymorphisms (SNPs) they had mapped on the twins' genomes.
Martin says it was a "Bingo!" moment when the results showed a big hit on chromosome one, right over the trichohyalin gene.
"This is a gene that has been known for well over twenty years as being involved in hair production and it's a gene that sits in the sheath that's around hair root bulbs," ABC Online quoted Martin as saying.
The study appears in the latest edition of the American Journal of Human Genetics.