Summary: Researchers have identified eight genes linked to red hair. The study also found almost 200 genes associated with hair texture, color and whether the hair grows straight or curly.
Source: University of Edinburgh.
Scientists have discovered eight genes linked to red hair. The study – which also sheds light on blondes and brunettes – is the largest genetic study of hair colour to date.
It had been thought that red hair is controlled by a single gene, called MC1R. The new research sheds light on other genes that are involved. Previous studies had shown that redheads inherit two versions of the MC1R gene that leads to red hair – one from their mum and one from their dad.
Although almost everyone with red hair has two copies of the red-haired version of MC1R, not everyone carrying two red-haired versions is a redhead. Scientists knew there must be other genes involved but these have mostly remained a mystery until now.
Now researchers at the University of Edinburgh have looked at DNA from almost 350,000 people who had taken part in the UK Biobank study. The study, which was led by The Roslin Institute and the MRC Human Genetics Unit, focused on people of European descent because they have greater variation in hair colour.
The genetics of hair colour and texture
Comparing redheads to people with brown or black hair, they identified eight previously unknown genetic differences that are associated with red hair. The team also looked at the functions of the genes they identified and found that some of them work by controlling when MC1R is switched on or off.
In addition to the redhead genes, the researchers uncovered differences in almost 200 genes associated with blondes and brunettes. Scientists say there is a gradient of colour from black, through dark brown to light brown and blonde, which is caused by increasing number of genetic differences in these 200 genes.
The researchers were surprised to find that many of these 200 genetic differences were associated with hair texture rather than pigmentation. Others are involved in determining how the hair grows – whether curly or straight, for example.
Funding: The study was funded by the UK’s Medical Research Council (MRC) and the Biotechnology and Biological Sciences Research Council (BBSRC).
Source: Jen Middleton – University of Edinburgh
Publisher: Organized by NeuroscienceNews.com.
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Original Research: Open access research for “Genome-wide study of hair colour in UK Biobank explains most of the SNP heritability” by Michael D. Morgan, Erola Pairo-Castineira, Konrad Rawlik, Oriol Canela-Xandri, Jonathan Rees, David Sims, Albert Tenesa & Ian J. Jackson in Nature Communications. Published December 10 2018.
[cbtabs][cbtab title=”MLA”]University of Edinburgh”How Redheads Inherit Their Flaming Locks.” NeuroscienceNews. NeuroscienceNews, 10 December 2018.
<https://neurosciencenews.com/genetics-red-hair-10316/>.[/cbtab][cbtab title=”APA”]University of Edinburgh(2018, December 10). How Redheads Inherit Their Flaming Locks. NeuroscienceNews. Retrieved December 10, 2018 from https://neurosciencenews.com/genetics-red-hair-10316/[/cbtab][cbtab title=”Chicago”]University of Edinburgh”How Redheads Inherit Their Flaming Locks.” https://neurosciencenews.com/genetics-red-hair-10316/ (accessed December 10, 2018).[/cbtab][/cbtabs]
Genome-wide study of hair colour in UK Biobank explains most of the SNP heritability
Natural hair colour within European populations is a complex genetic trait. Previous work has established that MC1R variants are the principal genetic cause of red hair colour, but with variable penetrance. Here, we have extensively mapped the genes responsible for hair colour in the white, British ancestry, participants in UK Biobank. MC1R only explains 73% of the SNP heritability for red hair in UK Biobank, and in fact most individuals with two MC1R variants have blonde or light brown hair. We identify other genes contributing to red hair, the combined effect of which accounts for ~90% of the SNP heritability. Blonde hair is associated with over 200 genetic variants and we find a continuum from black through dark and light brown to blonde and account for 73% of the SNP heritability of blonde hair. Many of the associated genes are involved in hair growth or texture, emphasising the cellular connections between keratinocytes and melanocytes in the determination of hair colour.