12 December 2018
The mystery of the orange hair was much more complicated than previously thought.
Children are thought to be born redheaded I was They need to inherit two copies of a gene called MC1R, one of the mother and one of the father.
on MC1R It is recessive gene, that is right can not occur in the presence of a dominant gene and only when the person receives copies of his mother and fatherhood.
However, not all people who inherit the MC1R gene have orange hair, a reason scientists have suspected that other factors play an important role they have not known so far.
Research of University of Edinburgh in the United Kingdom just showed why the gene MC1R only explains part of the puzzle. This is the largest genetic study done to the redheaded so far.
About 1 to 2% of the world's population is a redhead, but in Scotland, the rate is close to 13%, which is equivalent to 650 thousand people, according to the project ScotlandsDNA.
Scientists from University of Edinburgh they check the DNA of nearly 350,000 people who participated in the British project called United Kingdom Bioban, which gathers information on the health and genome of more than 400,000 people Great Britain
When researchers compare the genome of redheads to those of brown or black hair, they find eight differences related to the color of the hair. And they also found this some genes control when MC1R is expressed or not.
Orange Hair is not just the result of a recessive gene, but on complex interaction of at least eight genes.
In addition, the researchers check differences in nearly 200 genes related to people with blond or dark hair.
There is a gradient of color ranging from black to dark brown, light brown and blond. And that gradient is caused by an increasing number of variants in these 200 genes.
Something surprised scientists is that many of them these genetic differences are not related to pigmentation, but on the structure of the hair. Other variants determine how much hair grows, that is, whether straight or curly.
"Our work reveals most of the genetic variations that contribute to hair color differences", She said, Albert Tennesa, one of the researchers of the Rosslyn Institute from University of Edinburgh.
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