Tiny genetic mutation behind golden locks

Blondes have been both prized and mocked by people for their golden locks for ages.

PTI| Updated: Jun 02, 2014, 04:03 AM IST

Houston: Blondes have been both prized and mocked by people for their golden locks for ages.

There is, however, nothing accidental about their tresses according to a new study, which shows blondes can thank a tiny genetic mutation - a single letter change from an A to a G among the 3 billion letter in the book of human DNA.

Therefore, it is now clear that: they do have something special in their genes. The new research reveals how a single genetic tweak is enough to create blond hair in people.

"This particular genetic variation in humans is associated with blond hair, but it isn`t associated with eye colour or other pigmentation traits," said study leader David Kingsley, a Howard Hughes Medical Institute investigator at Stanford University.

He said the research shows how a specific gene "switch" might control colour changes in human characteristics.
Kingsley has spent much of his career studying a fish known as the three-spined stickleback in an effort to better understand evolution.

His research uncovered a gene that affects the fishes` pigmentation, and scientists decided to see if it has a similar effect in other species, like humans. Turns out it does.

"The very same gene that we found controlling skin colour in fish showed one of the strongest signatures of [gene] selection in different human populations around the world," Kingsley said.

In the new study, researchers found that a single letter of genetic code separates people with different hair colours.

"The genetic mechanism that controls blond hair doesn`t alter the biology of any other part of the body," Kingsley said. "It`s a good example of a trait that`s skin deep ? and only skin deep."

"Despite the challenges, we now clearly have the methods to link traits to particular DNA alterations," Kingsley said.
"I think you will see a lot more of this type of study in the future, leading to a much better understanding of both the molecular basis of human diversity and of the susceptibility or resistance to many common diseases."