Researchers Find Key Gene For Blond Hair In Solomon Islanders

A team of scientists has discovered a single gene mutation that contributes to the blond hair in dark-skinned Melanesians, which is absent in North American and European populations.

AsianScientist (May 9, 2012) – A team of scientists have discovered that the natural blond hair in dark-skinned Melanesians is caused by a single unique mutation in the TYRP1 gene, which is involved in the production of melanin.

Melanin is responsible for the color of a person’s skin and hair, and the hair color of an individual is largely influenced by the amount of exposure to ultraviolet (UV) radiation and the type and amount of melanin produced in the hair.

Populations living near the equator who are exposed to higher UV radiation generally possess darker hair and skin. This does not seem to be the case for the dark-skinned islanders from Melanesia, a group of islands northeast of Australia, as 5-10 percent of the population is found with naturally blond hair.

The team sought to look for the genetic origins of the blond-haired Melanesians as they were convinced that it was unlikely that Western traders who visited the islands in the past introduced the blond trait into the gene pool.

By comparing the DNA of 43 blond Melanesians and 42 dark-haired Melanesians, they were surprised to find that the blond-haired islanders were strongly associated with a single mutation in the TYRP1 gene. As the gene is recessive, the individual has to have mutations in both copies of the gene to inherit the blond hair trait.

To investigate if this gene was also found mutated in Western populations, the study also analyzed the DNA samples of 900 Melanesians and 900 individuals from populations worldwide.

Their findings revealed that the gene mutation was found only in populations living in the Oceania region, including Melanesia. This seems to suggest that the blond trait in the Solomon Islanders had evolved in an independent manner from Western populations.

The reasons behind the selection of the blond hair trait in Melanesians are still unclear, according to an accompanying editorial by Zoe Corbyn. Although blond people could be regarded as more attractive for potential mates, the evolutionary advantage of the blond hair trait in sexual selection has not been proven with strong statistical evidence.

The research team hopes to relay a critical take-home message from their study: the importance of studying the genetic makeup of populations worldwide to capture unique genetic traits or polymorphisms in less-studied populations.

The article can be found at: Kenny EE et al. (2012) Melanesian Blond Hair Is Caused by an Amino Acid Change in TYRP1.

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Copyright: Asian Scientist Magazine; Photo: Sean Myles/Nature Publishing Group.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Yuka graduated with a BSc (Hons) in life sciences from the National University of Singapore (NUS), Singapore, and received her MSc in cancer biology at University College London, UK.

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