Minor genetic quirk causes Melanesian Solomon people’s blond hair
About a quarter of the inhabitants of the Solomon Islands archipelago have dark skin and blond hair. Scientists have identified the reason for the unusual characteristic, dispelling the former belief that the blond hair originated from European genes.
The Solomon Archipelago is located in Oceania, east of Papua New Guinea. It consists in about a thousand islands and the population of over half a million people are mostly (95%) of Melanesian ancestry. Melanesian people are dark-skinned, probably the darkest skin colour outside of Africa. However, about one fourth of the Solomon Island inhabitants have blond hair in conjunction with their very dark skin.
This character had puzzled experts who until now have attributed the unusual trait as possibly inherited from the Europeans, particularly British, German and Australians who have been connected to the islands since the end of the 19th Century. In 1893, the United Kingdom declared a “Protectorate” over the southern Solomon. Other islands of the Archipelago were later added to the protectorate including areas previously under German jurisdiction. In the early 20th century, British and Australian companies established large coconut plantations in many of the islands.
Thus, the possibility of the blond hair trait in the dark-skinned Solomon People coming from European genealogy was not completely ruled out. However, the local people, according to The Salomon Times
, preferred to attribute their particular trait to a diet rich in fish or the constant exposure to the Sun.
Now, a group of researchers from the University of Bristol
in the UK, the School of Medicine, Stanford University, USA, and the Nova Scotia Agricultural College, Truro, NS, Canada, among others, have found a unique genetic mutation that explains the blond hair in the inhabitants of this region, and concluded that it is not related to the Europeans visitors, but must have originated independently of that possible genetic introgression
In their investigation, the researchers made a comparative study of the entire genome of 43 Solomon Melanesian people with blond hair and of 42 with dark hair. They identified a change in the gene TYRP1, known as “Tyrosinase-related protein 1”. The mutation is not great, only one amino-acid is different (arginine
is replaced by cysteine
). The researchers conclude that mutation in the gene TYRP1 appears to be responsible for the blond hair in Melanesian people.
“The mutation is at a frequency of 26% in the Solomon Islands, is absent outside of Oceania, represents a strong common genetic effect on a complex human phenotype, and highlights the importance of examining genetic associations worldwide."
say the researchers in their report
published on-line in the latest issue (May 4) of the journal Science.