An adventure of orange hair is much more complex than previously assumed.
Up to now it was assumed that for children to be born redhead, it was necessary that they inherited two copies of a gene called MC1R, one from the mother and another from the father.
MC1R is a recessive gene, that is, it can not manifest itself in the presence of a dominant gene and only does it when the person receives the mother and father copies.
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Not all people who inherit the MC1R gene have orange hair, so researchers suspect that other factors played an important role.
What these factors were was a mystery … until now.
A study by the University of Edinburgh in Britain has just shown why the MC1R gene explains only part of the puzzle.
The study, developed by researchers at the University of Edinburgh, is More genetic research on redheads so far.
Other researchers in Scotland previously tried to explain the key to orange hair.
About 1 to 2% of the world's population is redheaded, but in Scotland, the share is close to 13%, which corresponds to 650,000 people, according to the ScotlandsDNA project.
Researchers at the University of Edinburgh studied DNA of almost 350,000 people who participated in the British project that was called UK Biobank, which collects information on health and through more than 400,000 people in the UK.
When the researchers compared the redhead's genome with that of people with brown or black hair, they found eight differences in hair color.
And they also found it Some genes check when MC1R is expressed or not.
The orange hair is not just the result of a recessive gene, but of the complex interaction of at least eight genes.
Blonde and brown
The researchers also found differences in almost 200 genes associated with people with blond or dark hair.
There is a color gradient, ranging from black to dark brown, light brown and blonde. And that gradient is caused by an increasing number of variants in the 200 genes.
Some surprised researchers are that many of these genetic differences are associated not with pigmentation, but with the texture of the hair. And other variants determine how the hair grows, that is, whether it is straight or curled.
"Our work unravels most of the genetic variations that contribute to differences in hair color," he said. Albert Tenesa, one of the researchers from the Roslin Institute of University of Edinburgh.
Ian Jackson, genetic expert at the same center, said the work is an example of "Britain's biobanks power, a unique genetic study of the United Kingdom that allowed us to make these discoveries."
The survey was published in the journal Nature Communications.
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