“All people of non-European ancestry who have blond hair and blue eyes acquired those traits through gene flow from European ancestry.”

The lack of systematic ancestry differences between blond and dark-haired individuals in the study suggests that the higher prevalence of blond hair was not attributable to recent gene flow from European populations.

Here, we identify an arginine-to-cysteine change at a highly conserved residue in tyrosinase-related protein 1 (TYRP1) as a major determinant of blond hair in Solomon Islanders. … 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.

In Melanesia, particularly among Solomon Islanders, a derived allele in the TYRP1 gene has been linked to naturally occurring blond hair in the absence of European admixture.

Blond and dark-haired Solomon Islanders show no systematic differences in their ancestry suggesting that blond hair is unlikely to be due to gene flow from other populations (e.g. Europeans).

Naturally blond hair is rare in humans and found almost exclusively in Europe and Oceania. Here, we identify an arginine-to-cysteine change at a highly conserved residue in tyrosinase-related protein 1 (TYRP1) as a major determinant of blond hair in Solomon Islanders. … 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.

While admixture of Europeans in Native American populations is common, our studies overall show very low frequencies in our specific population samples except for the Maya sample (Fig. S4). Given the evidence of the variant in Northern Asia, the likely ancestral region for Native Americans, it is possible that the existence of the promoter variant at a low frequency in Native Americans is ancestral and not due to recent admixture. The same possibility applies to the presence in Australian Aborigines.

Most non-European populations have brown eyes and dark hair only. However, some populations from border regions between Europe and Asia populations (for example, groups from Altai region in Siberia, some populations from the Caucasus) are also known to carry lighter eye/hair phenotypes and these populations do not exhibit close relation with West Europeans on the genome level [13].

Melanesians, particularly those inhabiting Island Melanesia, possess some of the darkest skin pigmentation globally, with individuals from Bougainville displaying the highest melanin indices observed in any living human group ( Jablonski and Chaplin, 2000; Norton et al., 2006). … Its rs387907171-T variant (p.Arg93Cys), which has been widely identified as Melanesian blonde hair variant, also demonstrates a modest explanatory power (∼5.3%) to the variance in skin pigmentation (Kenny et al., 2012).

Our results suggest that adjacent cis-acting regulatory loci for OCA2 explain the relationship between skin and eye color, and point to an underlying genetic architecture in which several genes of moderate effect act together with many genes of small effect to explain ∼70% of the estimated heritability. … The derived APBA2 (OCA2) allele is present at low frequencies in most populations of African ancestry, and at high frequencies in most populations of Asian and European ancestry.

This research provides further evidence for lighter pigmentation evolving by means of selection at least partly independently in Europeans and East Asians but at some genes in common.

We report that the blue-eye associated alleles at all three haplotypes were found at high frequencies in Europe; however, one is restricted to Europe and surrounding regions, while the other two are found at moderate to high frequencies throughout the world. … In most of Central and East Asia, these alleles have frequencies of <20% but reach frequencies of 40% and higher in the Americas. … This research provides further evidence for lighter pigmentation evolving by means of selection at least partly independently in Europeans and East Asians but at some genes in common.

Several lines of research indicate that selective pressure for light pigmentation acted independently in Europeans and East Asians, yet with some genes in common. The brown-eyed associated SNPs frequent in Europeans are different from that of Asians, suggesting a population specific history of the genetic component of pigmentation19,27.

The fact that we did not detect reproducible associations with skin or hair color suggests that, unlike eye color, skin and hair pigmentation variation in Europe are not determined by major loci.

Given the absence of eye and hair color variation outside of Europeans and their direct geographic neighbors such as people from the Middle East and certain parts of Western Asia, it appears likely that eye and hair color variation arose in Europe via genetic mutations, and both the mutations and the derived non-brown eye color and the non-black hair color phenotypes increased in frequency due to sexual selection via eye and hair color preferences in human mate choice in Europeans.

Several lines of research indicate that selective pressure for light pigmentation acted independently in Europeans and East Asians, yet with some genes in common. … The brown-eyed associated SNPs frequent in Europeans are different from that of Asians, suggesting a population specific history of the genetic component of pigmentation 19, 27.

And contrary to long held belief, it seems golden hair hasn’t simply been introduced across the globe by travelling tow heads, but instead evolved separately in different human populations. … Until now, this odd trait had generally been attributed to the introduction of blonde genes by European explorers and traders in preceding centuries. … TYRP1 isn’t, however, one of the genes that produces blonde hair in Europeans.

As seen from Fig. 5 , for every individual who originates from regions that are distant from Europe and neighbouring regions, namely East Asia, Oceania, Sub-Saharan Africa and the Americas where only black hair is assumed to be present, HIrisPlex indeed predicts black hair as the only hair colour with no exception.

And contrary to long held belief, it seems golden hair hasn’t simply been introduced across the globe by travelling tow heads, but instead evolved separately in different human populations. … Yet a closer look revealed that the genetics behind blonde hair in Brussels are distinct from those leading to flaxen locks in the South Pacific. … TYRP1 isn’t, however, one of the genes that produces blonde hair in Europeans.

Therefore, the wide range of diversity in pigmentary traits across worldwide populations is mainly due to genetic variation that has been shaped by a range of evolutionary factors (i.e., drift, gene flow and selection)8–12. … Adding to this complexity, previous studies have identified the presence of allelic heterogeneity, in which different variants within a single gene are associated with pigmentation variation in different populations (e.g., MFSD12, OCA2)5,13,14, as well as the effect of multiple independent variants on the same locus associated with a diverse range of pigmentation tones within populations (e.g., HERC2/OCA2, MC1R, GRM5/TYR)5,15–19.

Most human populations around the world have brown iris color. Blue and green colors are found almost exclusively in people of European descent. … It should be noted that our findings are limited to individuals of European descent. It remains to be determined whether our markers are also associated with brown iris color in non-European populations.

The common occurrence of blond hair among the dark-skinned indigenous people of the Solomon Islands is due to a homegrown genetic variant distinct from the gene that leads to blond hair in Europeans, according to a new study from the Stanford University School of Medicine. … Further research revealed that the particular variant responsible for blond hair in the Solomon Islands is absent in the genomes of Europeans. … "So the human characteristic of blond hair arose independently in equatorial Oceania. That's quite unexpected and fascinating," Kenny said.

In contrast, populations in Europe and East Asia have independently evolved sets of genetic variants associated with lighter skin pigmentation. … For instance, lighter skin in Europeans evolved primarily through variants in SLC24A5, SLC45A2, and HERC2/OCA2, whereas East-Asian populations exhibit lighter pigmentation due to entirely different sets of genetic variants, such as those in DDB1, OPRM1, and other loci [10,24]. … In Melanesia, particularly among Solomon Islanders, a derived allele in the TYRP1 gene has been linked to naturally occurring blond hair in the absence of European admixture.

Here we dissect a regulatory region of the KITLG gene (encoding KIT ligand) that is significantly associated with common blond hair color in northern Europeans. … Mice carrying ancestral or derived variants of the human KITLG enhancer exhibit significant differences in hair pigmentation, confirming that altered regulation of an essential growth factor contributes to the classic blond hair phenotype found in northern Europeans.

These tools demonstrate high accuracy and reliability when applied to relatively genetically homogeneous populations, such as Europeans [2], [55]. However, their performance is considerably limited when applied to populations with high genetic diversity and complex admixture, such as the Brazilian population, where European, African, and Amerindian genetic contributions are intertwined [63], potentially favoring epistatic and pleiotropic effects not commonly observed in more genetically homogeneous groups.

Here, we identify an arginine-to-cysteine change at a highly conserved residue in tyrosinase-related protein 1 (TYRP1) as a major determinant of blond hair in Solomon Islanders. … 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.

The goal of this study was to determine the genetics underlying blond hair in the Solomon Islands, which has the highest prevalence of blondism outside of Europe.

The IrisPlex system was tested to predict eye color in 940 worldwide DNA samples; different eye colors were only predicted in European samples, while only brown eyes were predicted in samples from regions such as East Asia, Africa, Oceania, and Native Americans in accordance with the known global distribution of eye color categories [74].

Pigmentary phenotype is genetically complex and at a physiological level complicated. Genes determining a number of rare Mendelian disorders of pigmentation such as albinism have been identified, but only one gene, the melanocortin 1 receptor (MCR1), has so far been identified to explain variation in the normal population such as that leading to red hair, freckling, and sun-sensitivity.

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