Human hair color account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person's genotype for a multifactorial trait can interact with the environment to produce varying phenotypes (see quantitative trait locus). Natural hair color can be brown, blond, black, red, or white; all natural hair colors including grey, white and lightest blond, are shades of brown. The Fischer–Saller scale, named after Eugen Fischer and , is
Fawn (colour) use the term "fawn" to describe a red dog (at the Eumelanin locus) that carries a copy of the dilution gene; in Dobermans this color is more commonly called "Isabella". Fawn (colour) Fawn is a light yellowish tan color. It is usually used in reference to clothing, soft furnishings and bedding, as well as to a dog's coat color. It occurs in varying shades, ranging between pale tan to pale fawn to dark deer-red. The first recorded use of "fawn" as a colour name in English was in 1789. The fawn coat color is found in many breeds, such as