Inhabitants of Solomon Islands in the Pacific have darkest skin among people living outside the African continent. At the same time, ratio of natural blondes among these people is also much more than any other non-European populations, and scientists have discovered that the reason for this is a single gene.
Looks of Solomon Islanders have long been a cause of curiosity among experts because 10% of these people with very dark skin have blonde hair, which is not too much different from the proportion of occurrence of natural blondes among Europeans.
In order to solve this mystery, scientists at Stanford University analyzed DNA samples isolated from the saliva of 43 blonde-haired and 42 dark-haired people of Solomon Islands. The result obtained is a unique kind of exception to genetic patterns in which one symptom is usually formed under the influence of dozens of genes. It was found that mutation in single gene tyrosinase-related
protein 1 (TYRP1), localized in chromosome 9, explains the variation of hair color in the people on Solomon Islands. This gene encodes the enzyme, responsible for formation of human skin and hair pigmentation.
DNA Analysis of 941 individuals from among 52 human populations living around the world, including in Europe, in any case did not reveal the mutation. It was found out that the mutation occurred independently and persisted in the genes of Melanesian population, and light hair color is the result of neither cross breeding with Europeans, nor bleaching under the sun and sea water, which is a symptom unique for this group of people.
Melanesian TYRP1 gene variant differs from the variant which is responsible for blue eye color, and it according to experts, appeared 6,000-10,000 years ago. Prior to this blue-eyed people simply did not exist in nature, reports Science Mag.
Researchers note that the discovery of special variant of gene TYRP1 is an interesting solution to the genetic riddle, but it once again points to the dangers of extrapolating the results of genetic studies of different ethnic groups. Problem is that, like hair color, any sign may be the result of completely different genetic mechanisms in different groups of people. Therefore, approaches to treatment of diseases, based on genetic information, should be carefully checked for people from wide range of populations. Otherwise, drugs may help some people, and can cause harm to others.
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