Manuel Corpas' Blog

Is it weird for a Spaniard to have red hair? The typical stereotype for a Mediterranean person is brown-skinned, not too tall and with dark hair. I do not seem to fit all those stereotypes very well, except for the dark hair. At least so I thought until I posted this picture of my beautiful family on my Facebook profile:

How is it possible that my children have the red hair gene expressed so dominantly? I have dark hair and my parents do so too!

Of the five of us I am the only one without red hair. Seeing this picture really brought it home to me, it was strange that everyone of my three children had inherited my wife’s ‘recessive’ red hair!

I did not give a lot of importance to this until my colleague and Facebook friend Dave Adams, who happens to lead a research group at the Wellcome Trust Sanger Institute, asked me whether I had checked the MC1R gene.

The protein encoded by the MC1R gene is found in melanocytes, the cells that give hair and skin their color. The variants associated with red hair alter the protein’s function, tipping the balance of pigment production in melanocytes from black-brown eumelanin to red-yellow pheomelanin [1].

Dave is well aware of my efforts to crowdsource my genome data analysis and those of my blood relatives (parents, siblings and aunts and uncles). Since I have had my exome done, and following Dave’s suggestion, I looked for the animo acid changes he suggested (r151c, r160w and d294h) in the MC1R gene. Below you can see some of the comments of our conversation on Facebook:

Facebook chat showing Dave Adam’s conversation with me about finding the origin of the red hair in my offspring.

I have a VCF file for all variations in my genome available in figshare for public download. I searched the file for the 89978527-89987385 interval in which the MC1R gene is located in chromosome 16 and found:

16 89986091 rs11547464 G A

This indicates that in position 89986091, there is a small change of one letter (SNP rs11547464) that makes my DNA in that position differ from the one of the human genome reference. The reference genome has a G whereas I have an A.

I also looked at my 23andMe genotype using myKaryoView, which also includes this rs11547464 SNP, and found that my genotype is ‘AG’. Doing some research with this I found that AG in the rs11547464 SNP encodes a missense change on the protein sequence (R142H), making me a ‘carrier’ state for ‘red hair’ [2].

More information about the relation of this SNP the phenotype showed that this mutation has been shown to be deleterious [3] and that this MC1R variant is “functional” [4].

According to Dave, I am a carrier for this red hair mutation and presumably my wife is homozygous for another variant with my kids being compound heterozygous. This means that perhaps my wife has another variant somewhere that also contributes to my children having red hair.

This explains, at least partly, how my offspring’s red hair is so strong, something that in principle should be self evident from the picture above. There is something satisfying though about being able to confirm the obvious with scientific evidence.

References

[1] http://blog.23andme.com/news/snpwatch-researchers-find-link-between-red-hair-and-avoiding-the-dentist/

[2] http://www.ianlogan.co.uk/23andme/open/nancy-grossman.htm

[3] http://www.medwelljournals.com/fulltext/?doi=javaa.2011.928.931

[4] http://blog.23andme.com/news/snpwatch-researchers-find-link-between-red-hair-and-avoiding-the-dentist/