Hair Color and Skin Pigmentation in Europeans

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A Genome-Wide Association Study Identifies Novel Alleles Associated with Hair Color and Skin Pigmentation:

It has been a longstanding hypothesis that human pigmentation is tightly regulated by genetic variation. However, very few genes have been identified that contain common genetic variants associated with human pigmentation. We scanned the genome for genetic variants associated with natural hair color and other pigmentary characteristics in a multi-stage study of more than 10,000 men and women of European ancestry from the United States and Australia. We identified IRF4 and SLC24A4 as loci highly associated with hair color, along with three other regions encompassing known pigmentation genes. Further work is needed to identify the causal variants at these loci. Improved understanding of the genetic determinants of human pigmentation may help identify the molecular mechanisms of pigmentation-associated conditions such as the tanning response and skin cancers.

….Taken together, these four regions explain approximately 21.9% of the residual variation in hair color (black-blond) after adjusting for the top four principal components of genetic variation. (Conversely, after adjusting for these four regions, the top four principal components of genetic variation explain 2.6% of the residual variation in hair color.)….

There are four regions because areas around HERC2/OCA2 and MAPT showed signals. MAPT is also known as AIM1 and SLC45A2, so this makes 3 genes of the potassium-dependent sodium/calcium exchangers implicated in pigmentation (the other is SLC24A5 obviously). They adjusted for the components of genetic variation so as not to be confounded by population stratification (i.e., there was some ethnic variation among their whites and so you don’t have a random mating population).

It’s in PLOS; you can read the whole thing, etc.

Related: Why white people are so colorful!. Sandy also comments.

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6 Comments

  1. I was a blonde bairn, becoming a brunette adult, but with a lot of ginger in sideburns, ‘tache and beard, and with light brown hair on my arms. My eyes are grey-blue. 
     
    Has that combination got a name?

  2. these studies focus on adults. so you’re a brunette. as for variation in hair color…one thing at a time i suspect ;-)

  3. My wife wants you to know that my arm hair shimmers gold and red in the sun. Bless her.

  4. …Taken together, these four regions explain approximately 21.9% of the residual variation in hair color (black-blond) after adjusting for the top four principal components of genetic variation. (Conversely, after adjusting for these four regions, the top four principal components of genetic variation explain 2.6% of the residual variation in hair color.)… 
     
    I don’t get it. The four PCs explain 21.9% but then only 2.6%. Uh?! 
     
    In any case they seem to explain way too little – but 22% is a much larger little chunk than 2.6%, that seems nearly irrelevant.

  5. I don’t get it. The four PCs explain 21.9% but then only 2.6%. Uh?! 
     
     
    2.6% is stuff they assume is due to population substructure within the sample (a small minority of australians are of predominant italian ancestry which might result in spurious correlations) and what not i think. the 21.6% is for the 4 genes.

  6. Ok, thanks.  
     
    So we have about 1/5 – 1/4 of pygmentation apparently explained genetically with this study. Not bad but still a lot to discover.

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