Light skin of UVA can penetrate deeply into the dermis in persons with light skin pigmentation with little protective melanin pigment. The characteristic of fair skin, red hair, and freckling is associated with high amount of pheomelanin, little amounts of eumelanin. This phenotype is caused by a loss-of-function mutation in the melanocortin 1 receptor (MC1R) gene. However, variations in the MC1R gene sequence only have considerable influence on pigmentation in populations where red hair and extremely fair skin is prevalent. The gene variation’s primary effect is to promote eumelanin synthesis at the expense of pheomelanin synthesis, although this contributes to very little
Dominant white there is pigmented skin on the coronary band just above the hoof. In some cases, foals born with residual non-white hair may lose some or all of this pigment with age, without the help of the gray factor. Dominant white spotting does not affect eye color, and most dominant white horses have brown eyes. The pink skin is devoid of pigment cells (melanocytes), and appears pink from the underlying network of capillaries. White hair is rooted in unpigmented pink skin. There are many other genetic factors that produce white, near-white, and off-white coat colors in horses, some of which are