A traveler who has arrived in Melanesia can be truly shocked: only here you can meet a large number of dark-skinned people with blond hair. Scientists have long tried to figure out the reason for such an atypical appearance. Researchers of the 19th century said that the hair of the islanders was dyed with coral lime. Others speculated that the hair quickly faded from the tropical sun and salt water, in which the locals splash. More sophisticated ones suggested that the brightening was due to a diet rich in fish.
Finally, as usual in such cases, it was not without reasoning about the admixture of European blood.
Melanesia is an island group in the Pacific Ocean, which includes New Guinea, Fiji, Vanuatu and other states. Among the inhabitants of the islands, every tenth is blond. Considering that the population of Melanesians is about half a million, the phenomenon can be called typical and widespread. Interestingly, along with blond hair, the Melanesians inherited from their ancestors pitch-dark skin.
The main version that genetic scientists have put forward for several years was heredity. They remembered that the British and Germans lived on the islands in the 19th and 20th centuries, they grew coconut plantations here.
In fact, back in the middle of the 20th century, serious anthropologists wrote that light hair color repeatedly appeared independently in isolated populations almost all over the world. Blond Australian aborigines, Indians, Evenks, highlanders of the Caucasus, Atlas and Hindu Kush are known. The influence of the European admixture was reasonably rejected in all these cases, and the appearance of relatively light-haired populations was associated with the effects of the founder and the bottleneck (see about them on our portal). European blonde hair is unique only for its huge range and high frequency of occurrence.
However, it is one thing to talk about genetic-automatic processes, and another thing to find a specific gene responsible for lightening hair. This is what an international group of geneticists did. The remarkable case of the Melanesians is that they have only two hair color options: black and white. Therefore, the researchers immediately suggested the presence of only one simple mutation in one gene. It remains "just" to find it and confirm the guess. To do this, it was necessary to collect samples of saliva and hair from 1209 islanders. Of this wealth, however, only 43 “blondes” and 42 “brunettes” went into business - grants are not rubber either. The rationale for the article, of course, was found more solid: they say, since all phenotypes are literally one or two, and is it worth it to spend extra energy?
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Among the islanders, 10% are blondes, but 26% have a recessive mutation in the protein synthesis gene that determines hair pigmentation. The result has already been tested on 918 Melanesians in the Solomon Islands and 941 in other parts of the planet. The "Solomon" mutation turned out to be simple, but not found anywhere else in the world. The notorious ubiquitous Vikings of Thor Heyerdahl, apparently, sailed past Melanesia (were they in a hurry to Easter Island or South America?); on the other hand, the Melanesians also did not particularly disperse from their tropical paradise.
In Europe, light hair color is usually determined by a whole combination of genes, but in the Solomon Islands, blondes differ in one single gene, TYRP1, located on the ninth chromosome.
Such a gene mutation does not occur in Europe; it is a distinctive feature of the population of Melanesia. In general, the structure of the human genome turns out to be very different in different populations - the same properties can be encoded by different genes.
Well, the assumptions made more than half a century ago have been brilliantly confirmed. Blond hair is different from blond hair! Isolation and polymorphism work wonders. It remains for geneticists to analyze the genes of Kabila, Mandan, Aranda, Evenk and Khanza …
Interestingly, scientists explain a large number of blondes by the fact that blond women are more attractive to men, and most often marriages are concluded with them.
Unlike light hair coloration, blue eye color in all people is due to a single gene mutation that occurred at some point between the 8th and 4th millennia BC. All blue-eyed people on the planet have a common ancestor who lived at that time. Before blue-eyed people simply did not exist.
Read more about blue-eyed here.