Hair Characteristics - Variation in Faces
Disclaimer: As with all characteristics in this activity. Genotypes, number of alleles, and the inheritance patterns have been simplified.
Hair Color
Hair is another case where several genes influence the color of one's hair. On top of that these genes can be switched on or off which explains why a person's natural hair color can change (without coloring by a stylist). It is well understood the your hair color is produced by a pigment called melanin. This is same pigment found in skin cells that determine skin tone or color. There are two types of melanin: eumelanin and pheomelanin. The amount of eumelanin and pheomelanin produced by the cells in the hair follicle determine your hair color.
Two pigments work differently. The eumelanin pigment works in this way: if your hair has lots of eumelanin it will be black; if your hair has little eumelanin it will be blonde. Pheomelanin is responisble for producing red hair. The more pheomelanin present in your hair the redder it will look.
As an example, individuals with "strawberry blonde" hair have a little eumelanin and a little pheomelanin in their hair. Someone with "auburn" hair would have a bit more eumelanin abd pheomelanin. An individual with red hair would have very little eumelanin and lots of pheomelanin.
The genotypes shown below do not match the actually genotypes and are simplification of the genotypes for our activity. Go to the following links to learn more about the genetics of hair color
Hair Color Genetics - Links from The Tech Museum (San Jose) & the Stanford University Department of Genetics
