The Grapevine

Gray Hair Gene Identified, Along With Those For Curly Hair, Beard Thickness, And The Monobrow

gray hair
Scientists identify the genes behind gray hair, curly hair, beard thickness, and even the humble monobrow. Ryan McGuire, CC by 2.0

Some genes decide the color of your hair, while other, considerably less friendly genes influence whether or not you go bald. Now, a University College London study has identified the DNA behind gray hair, curly hair, beard thickness, and even the humble monobrow. The researchers say their results confirm long-held suspicions nursed by unmarried aunts — going gray simply runs in the family.

We humans have lost most of our body hair over time, yet the abundance of head hair we’ve managed to retain throughout our evolution varies tremendously from individual to individual, and not just among those who regularly drop a Benjamin at the salon. According to the researchers, the appearance of our hair is mostly an inheritance game as evidenced by the obvious differences appearing on different continents. For example, straight hair is virtually absent from sub-Saharan Africa, while variable hair color is mostly found in West Eurasia.

“Interestingly, different genes have been associated with straight hair in Europeans and East Asians, suggesting that this trait evolved independently at least twice,” wrote the team of researchers led by Dr. Kaustubh Adhikari.

Hair Diversity

Adhikari, of UCL’s cell and developmental biology department, and his co-authors analyzed 6,357 people with varied ancestry across Latin America to identify new genes associated with hair color, greying, density, and shape (curly or straight). The hair volunteers, 55 percent women, came from Brazil, Colombia, Chile, Mexico, and Peru. The group included people with a wide variety of hair, from a wide variety of backgrounds, including mixed European (48 percent), Native American (46 percent), and African (6 percent).

After assessing the volunteers’ hair, the team compared individual features to whole genome results in order to identify which genes influenced appearance.

The gene matching gray hair is IRF4, which also plays a role in hair color, the researchers said. In fact, this helps regulate production and storage of melanin, the pigment that influences hair, skin, and eye color. Gray hair is caused by an absence of melanin so understanding more about how this works could contribute to the development of new cosmetics that block or delay the gray before it begins, the researchers imagine.

The researchers also discovered that gene PRSS53 influences hair curliness; EDAR, beard thickness and hair shape; FOXL2, eyebrow thickness; and PAX3, the monobrow.

These findings may also be used for more serious purposes, such as helping scientists create forensic technologies for establishing a visual profile based on an individual’s genetic makeup, the researchers said. Prototypes in this field have already been developed based on samples derived exclusively from people of European descent. These new results would flesh out investigative reconstructions in Latin America and East Asia.

The study results may also help researchers better understand the biology of aging, the team said. Apparently, Adhikari and his co-authors don't seem to understand that simply identifying the gene behind gray hair, which could lead to permanently ending the "salt and pepper" look, is plenty good for most of us.

Source: Adhikaria K, Fontanil T, Cal S, et al. A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features. Nature Communications. 2016.

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