Small Switch in Gene Codes Can Give You Blond Hair: Study

Scientists discovered a genetic code that makes the hair blond.

Experts from the Stanford University found different genetic codes that make the hair blond or brunette. A small switch in the DNA code can change the color of the hair without affecting the skin or eye color.

"This particular genetic variation in humans is associated with blond hair, but it isn't associated with eye color or other pigmentation traits," says David Kingsley, an HHMI investigator at Stanford University in a news release. "The specificity of the switch shows exactly how independent color changes can be encoded to produce specific traits in humans."

The researchers closely observed the three-spined stickleback, a type of fish, for more than a decade to understand its evolutionary changes and skin color variations. Their analysis revealed a gene 'Kit ligand' that controls pigmentation and color changes in both fish and humans. Their study involved mice that have genetic structure similar to humans. It was noted that a small change in gene expression of 20 percent gave them light golden fur. Mice with DNA code A had brown colored fur that trued light brown at code G.

"This is a good example of how fine-tuned regulatory differences may be to produce different traits," Kingsley said. "The genetic mechanism that controls blond hair doesn't alter the biology of any other part of the body. It's a good example of a trait that's skin deep-and only skin deep."

Apart from influencing the color of the skin, Kit ligand impacts the behavior of stem cells, sperms and neurons in the intestines.

"We think the genome is littered with switches," he says. "And like the hair color switch, many of the regulatory elements that control Kit ligand and other genes may subtly adjust activity. "

The authors believe these findings aid in understanding specific traits in humans and also their resistivity to many diseases.

More information is available online in the journal Nature Genetics.