About one - quarter of the Melanesian population in the Solomon Islands archipelago is quite unusual features - dark skin with blonde hair . The archipelago , located to the east of Papa New Guinea in Oceania , is composed of a thousand islands inhabited by more than half a million Melanesian people . These are the darkest skin in the world outside of Africa , but curious , about one- fourth of the inhabitants blonde sport Afros .
This rare Melanesian features are baffled scientists and genetic experts for years . Up until now , they have attributed the differential inheritance - from European , especially British , German and Australian , have been associated with the island for hundreds of years . Many of the island was under German jurisdiction in the 19th century . In 1893, the UK took the southern Solomon Islands under their wing , declaring the region a protectorate. The rest of the island was added to the protectorate at a later stage . And in the early 20th century , the Australian and British companies set up coconut plantations in many of the islands .
So it's not completely unbelievable that the dark -skinned Melanesians got their blonde hair from growing influx of ' outsiders ' . The local, however , prefer not to go through that theory . They have been insisting for years that their blond hair is a result of a diet rich in fish and constant exposure to the sun . As it turns out , both theories are quite far from the truth . According to a recent survey , random mutation may actually be the answer to the mystery of the Melanesian blonds .
Sean Myles , the author of the study and geneticist at the Nova Scotia Agricultural College , pointed out that there is almost no variation in shades of blond hair . This suggests that the color of hair is governed by the gene . " It looked pretty obvious to me that this is a true binary trait , " he said . " You had either blonde hair or you did not . " To find the underlying plan to Melanesian genetic pool , Myles and his colleagues collected saliva and hair samples from more than 1,200 Solomon Islanders . From the sample , they compared the genetic makeup of 42 with black hair and blonde 43 islanders .
What the scientists discovered was pretty impressive - the two groups possessed very different versions of an essential gene , TYRP1 , which coded for a protein involved in pigmentation . Moving just one letter of the genetic code (a ' T ' rather than a ' C ' ) , marked the difference between the dark hair and blonde hair . Only one amino acid in the protein variant ( arginine replaced by cysteine ) . So 25 percent of Solomon Islanders carry two copies of the recessive mutant gene . That means the blonds would inherited their hair color from both parents . " This is an excellent example of convergent evolution , where the same result is brought about by a completely different way , " says Myles .
Jonathan Friedlaender , an anthropologist at Temple University Philadelphia , explained that the mutation probably arose by chance in an individual . Appears to have gained in frequency as the original population of the island is relatively small . Myles added : " If you can find a gene for blond hair that exists in Melanesia and nowhere else , then there is no reason why these types of gene did not exist throughout the world underrepresented populations , and affects not only hair pigmentation , but the disease is also related to this characteristic . "
The study also traced the origin of the Melanesian people in an effort to understand the mutant gene . They discovered that while all people outside Africa that gene passed down from Neanderthals , Melanesians knew the people with different prehistoric tribes . They are believed to have evolved from a Denisova hominin interbreeding of , distant cousin of Neanderthal man . So the islanders have slightly different gene , which gives them their distinctive blond hair .
0 comments:
Post a Comment