Dysplastic melanocytic nevi contain high levels of
pheomelanin: quantitative comparison of pheomelanin/ eumelanin levels between normal skin, common nevi, and dysplastic nevi.
The reddish color displayed by azure sand grasshoppers has recently been reported to be related to the presence of
pheomelanin, a pigment formerly thought to be restricted to vertebrates only.
Lamoreux et al., "Slc7a11 gene controls production of
pheomelanin pigment and proliferation of cultured cells," Proceedings of the National Academy of Sciences of the United States of America, vol.
Pheomelanin, that is responsible for red hair and freckles in humans and orange and chestnut coloration in other animals, is known to increase the damage to skin cells and melanoma risk when present in large amounts.
Since all melanin-based color is formed by a combination of two melanin pigments, eumelanin (which makes dark colors) and
pheomelanin (which makes yellow to red colors), they speculated that eumelanin may be more susceptible to degradation than
pheomelanin pigments, which overtime could lead to reduced proportion soft his pigment in the feathers, ultimately resulting in higher reflectance at longer wavelengths (i.e., giving the feathers a slightly reddish color).
Melanin is the substance that gives skin, hair and eyes their colour, dependent on the relative amounts of the two forms of melanin, eumelanin and
pheomelanin. People who produce mostly eumelanin tend to have brown or black hair; those who produce mostly
pheomelanin tend to have red or blond hair (4,5).
Redheads have more of another pigment called
pheomelanin.
Melanins are classified in: Allomelanin (Allo) present in plants and fungi, Neuromelanin (Neu) present in nervous cell,
Pheomelanin (Pheo) and Eumelanin (Eu) that can be found in the skin, hair and iris.
The sulfur content of the amino acids cysteine and methionine promotes the abundance of the lighter-skin pigment
pheomelanin. Thienna discovers that the first humans were black; but sulfur-rich lower-toxin diets lightened the skin of early agricultural peoples.
The presence of some MC1R variants fails to shift the production from red/yellow pigment (
pheomelanin) to black/brown pigment (eumelanin), causing less efficient protection against ultraviolet radiation.
Specimens captured in the different localities presented the following characteristics with respect to the fur coat and coloration: the dorsum had short guard hairs (9-10 mm), with a yellowish
pheomelanin portion, giving the back an agouti colour.