The Gene That Causes Gray Hair Has Been Identified

gray hair
It turns out graying hair isn't necessarily due to stress. REUTERS/Carlos Barria

It’s well known that graying hair is caused primarily by genetics; if your parents went gray, you probably will, too. However, it’s only now that scientists have pinpointed exactly which gene may be responsible for this color change.

A study published March 1 in Nature Communications identifies the primary gene responsible for gray hair, and argues that the finding could useful in the field of forensic science. One day, it could also lead to the development of a pill that prevents the salt from overpowering the pepper on your head.

For the study, researchers analyzed the DNA of 6,000 people from Latin America (Brazil, Colombia, Chile, Mexico and Peru) to locate the genes that determine hair color, texture, density and other attributes such as whether a person’s hair is straight or has corkscrew curls. The study cohort included people of mixed European, Native American and African origin, giving the researchers a diverse variation of gene pools.

Kaustubh Adhikari, a professor of cell and developmental biology at the University of College London and lead author on the study, says it was already known that the newly identified gene—IRF4— is responsible for light hair color in people of European origin. But this is the first time researchers have shown that it’s also tied to gray hair color.

The gene is tasked with regulating and producing melanin, the pigment that gives hair its color. (Melanin is also is responsible for the color of eyes and skin.) Gray hair occurs, in part, when the body starts producing less melanin. When and how much melanin the body produces is determined by genetics.

“As hair grays something happens that causes this gene to produce even lower levels of melanin,” says Adhikari. “Now we can ask more specific functional questions.” And asking the right questions will then put them one step closer to identifying therapies that delay hair graying.

According to the researchers, there is growing interest in developing therapies that alter the DNA attributes of hair before it actually emerges from the scalp. Up until now, the industry has focused primarily on changing the appearance  of hair once it sprouts from the head.

In total, the researchers identified 18 genes that appear to influence the look and feel of hair. They found one gene linked to hair shape. In particular, gene PRSS53 was found to be responsible for hair curliness. This gene is the driver behind the production of a certain enzyme that prompts the hair follicle to produce a certain shape.  The study also identified genes related to beard and eyebrow thickness and unibrow.

These findings may be especially useful to the field of forensics and anthropology. For example, in some criminal cases there are biological samples but sometimes insufficient eyewitness information to help investigators identify a suspect. Information on which genes are responsible for certain hair traits might help to unravel a case.