Alternative Names
Strawberry Blonde; Auburn Hair; Burgundy; Ginger; Redhead
What is Red Hair?
Hair color is primarily determined by two types of melanin called pheomelanin and eumelanin.
Eumelanin determines the darkness of hair color. Eumelanin has two subtypes: black and brown. In the absence of other pigments:
- A low amount of brown eumelanin results in blonde hair.
- A higher amount of brown eumelanin results in brown hair.
- A high amount of black eumelanin results in black hair.
- A low amount of black eumelanin results in gray hair.
Pheomelanin colors hair red. Although all humans have varying amounts of pheomelanin in their hair, in general, most redheads have higher amounts of pheomelanin and lower amounts of eumelanin. The varying shades of red hair color are caused by a mixture of how much eumelanin and pheomelanin is present in the hair.
How Common Is It?
Red hair color is the rarest hair color in humans. About 1-2% of the world's population has red hair, but it is more common in people of Scottish and Irish descent. The United States has the largest population of redheads in the world, as approximately 6 million Americans have red hair.
Genetics & Inheritance
In general, hair color is determined by multiple genes and the inheritance of hair color is complex and not yet completely understood. However, red hair is known to be associated with specific variations in the MC1R gene.
Several MC1R variants have been shown to have strong associations with red hair (and pale skin). Most people with red hair have two copies of the same "red hair variant" or two copies of different "red hair variants." People with one copy of a "red hair variant" and one copy of a "non-red hair variant" are called carriers and typically do not have red hair. As such, red hair is often said to have autosomal recessive inheritance.
Other genetic variations also likely play a role in determining red hair color.
Genetic Testing
Informational genetic testing for the some of the genetic variations associated with red hair color is available online (over the internet). In addition, informational genetic testing for red hair color is also available as part of a whole genome scan. Whole genome scanning involves analyzing thousands of small genetic variations at once related to a number of different health conditions and traits. Go to the Tests tab to link to the best providers, compare providers and read provider reviews.
More Information
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