... COLORS ...
The Sheltie colors come in three broad strokes: sable, black, and blue merle.
Within these categories, Shetland Sheepdog colors offer varying amounts of tan, mahongany, black, gray and white, to make a variety of beautiful combinations - officially known as sable, tri color, bi black, blue merle and bi blue. feature patches of white around the neck, chest, legs, and toes in what's called an "Irish" patten, common to all the Sheltie coats.
Conspicuous white body spots (other than the normal distribution of white on the chest and legs) also lose points. Shelties with more than 50 percent white fur are disqualified. Yep, dog standards are pretty strict, and they need to be because that's how breeders maintain the specific look of the Shetland Sheepdog breed.
The sable Sheltie color arises from a dominant allele (gene variant).
This dominance makes it the most common coat color among Shelties. Curiously, sable Sheltie puppies are born with subtle hues which deepen and intensify with the development of the double coat.
The sable color may develop further as the dog matures - as does the thickness and quality of the double coat.
The classic Sheltie, sables range from light gold to mahogany.
Bi black Shelties comprise of solid black hairs which make up most of the coloring, alongside Irish patches of white fur. Bi black Shelties are so named for their black-and-white mixture, where bi is Latin for two. They fall under the umbrella term of black Shelties.
he bi black Sheltie allele is recessive, which makes it the least common type of Sheltie color. Interestingly, the opposite is true in many other dog breeds, where black is the dominant allele. To produce bi black puppies, breeders either need one or both parents to be bi black too. That said, breeding two tri colors (see below) can also produce a few bi black puppies if both parents are carriers of the recessive black allele.
ri color Shelties are a gorgeous combination of black, white and tan. They fall under the black Sheltie category too. As per the Irish pattern, the white fur appears on the chest and legs. The tan fur is usually found on the cheeks, throat, ears, eyes, legs and under the tail.
You'll see a few more tri color Shelties around thanks to their genetics: tri color is recessive to sable, but dominant to bi black. Shelties with both sable and tri color alleles are known as "tri factored" and can pass on either coat color to their puppies.
THE BLUE MERLE
Blue merle Shelties could be considered tri color Shelties with color modifications. This creates a coat in which the black hairs are diluted into various shades of gray-blue. There's also the white and tan dsitribution of a regular tri color.
Unlike the Sheltie colors seen so far, merle Shelties are not produced by color genes. Instead, they are created by a color modifier gene which affects the base color of the dog (black or sable). The same modifier gene can also give the dog either one or two blue eyes.
Breeding two blue merles has a 1 in 4 chance of creating a double merle - and this has serious health consequences. While it results in a stunning all-white coat, the lack of melanin drastically impacts development of the eyes in the womb. Many double merles are born blind, or deaf, or both.
Bi blue Shelties have only blue merle and white colors (ie - no tan).
Like the other Sheltie colors, the overall pattern is Irish with a white chest and legs. They have varying degrees of mottling, and the eye color can be blue or merled.
A bi blue is created when a bi black Sheltie meets a merle modifier. It's fairly unusual to see, although careful Sheltie breeders can manipulate their odds of producing bi blues by having a handle on the underlying genetics. They are healthy dogs, possessing only one merle gene, as opposed to two merle genes which creates the blind double merle.