Red hair

[JohnnyGus]

I wonder why there are so many natural shades of ginger hair. Some people are bright red, others auburn, some strawberry blond, etc. I know there is a gene for red hair but I wouldn't have thought 1 gene could produce all those colours. I know two red haired people who have no parents with red hair. It looks like the genetics of hair colour is complicated.

[B00]

I should imagine its the same as the many shades of brunettes you can get or blondes...no?

[JohnnyGus]

I looked up about hair colour and found that there are two pigments in peoples hair. One gives a yellow colour when at a low level and a red colour at a high level. The other pigment gives blond when at a low level, brown at a medium level and black at a high level. Our hair colour is decided by the amount of each pigment and the ratio of the two pigments. So someone with auburn hair would have a more even ratio of the two pigments in their hair than someone with bright red hair. A mutation in a gene causes red hair. The gene works by incomplete dominance, so someone with a double copy of the mutation will have brighter red hair than someone with a single copy.

[B00]

Oh