27/10/2019
Pure White Bully
White may not be color but it is still controlled by its own set of rules. We can use white to control the distribution of pigment as well. Most white spotting on dogs is determined by the genes on the S locus. When we use the term "white spotting" we simply mean white areas on the dog, not actually white spots. White spotting can occur on any color, and will cover up both eumelanin and phaeomelanin. So any dog can have white markings, whether they're black, blue, platinum, liver, isabella, pearl, brindle, sable, tan-pointed, merle or whatever. White hair occurs when the skin cells are unable to produce any pigment. The white spotting gene impairs the ability of cells on particular parts of the skin to make pigment, so the skin becomes pink and the fur white. Nails and paw pads will also become pink in areas where pigment is not produced. The range of white patterns can be bred true leading researchers to believe each pattern, white-spotting, split faces, white heads, irish spotting, psuedo-irish, extreme white, and piebald are controlled by their own modifiers.
The white rules aren't set in stone - sometimes individual dogs can have unusual white patterns, where, for example, the white on the legs is very uneven, or they have piebald patches in unexpected places, like on the neck or chest. However, in general, they do hold relatively true. Extreme dilution of the phaeomelanin can turn tan points to a light cream. Many people enjoy the varies patterns white creates. Im interested for one other reason. Any white areas on a dog, no matter how big or small, may be ticked or roan due to the T gene. Ticking or roan cannot be expressed if the dog does not have white areas...and this is where we leave the intermediate level and venture into the advanced area of coat colors and conditions.