A different sort of diluted dog has been found by a Florida Shih Tzu rescue. She resembles the albino dogs described in literature.
This is Angel, the Shih Tzu with the mystery color mentioned in my previous post. When my friend Gretchen contacted me, she wondered if Angel might be a pale lilac dilute. That is a dog that has both the blue dilution (dd) and brown (bb). The palest shades of lilac are usually the lightest color, aside from white, that most dog owners are likely to see. Angel’s skin is not a muted brown, though, but a clear pink – quite a bit lighter than would be expected in a lilac dog.
Although lilac dogs have the palest overall tone, when it comes to skin coloring the lightest colors can often be found in recessive red dogs that are also homozygous for brown (ee and bb). In Labradors, this combination is sometimes called Dudley. As this comparison image shows, Angel’s nose color (left) is considerably lighter than the one on the Dudley Labrador (right).
The pink skin was consistent on the pads of her paws as well. This extreme absence of skin pigmentation is particularly striking to anyone accustomed to looking at dogs. As I mentioned in the previous post, dogs do not have pink skin under their white markings in the same what that a horse will. Unlike horses, white markings that cover the nose do not give a dog a pink nose. Dogs seem very inclined to retain at least some pigment in their skin, which is what makes a truly pink-skinned dog stand out.
Historically, dogs like Angel have been called albinos. That is true even though most have blue, green or even hazel eyes. They also have traces of color in their fur, making it possible to discern hints of things like black-and-tan patterns, black masks or white markings. To someone immersed in the world of horse color, that would sound like a mistake. It is an article of faith in the horse color community that albinos must be white with pink or red eyes. Yet albino is the term used not only by owners and breeders, but in scientific literature. Researchers have told me that albino is a term that can be used strictly or more loosely. That is one reason why it is so very difficult to get a definitive answer to the question, “Can a true albino have blue eyes instead of pink?” It really does depend on who you ask!
I had first become aware of dogs like Angel when I stumbled across a paper on albino Pekingese when doing research on the Hanoverian Creams. I was also aware of a handful of of other more modern cases, mostly among the smaller Asian breeds. What I did not realize until I began looking was that while still quite rare, this type of coloring is more widely distributed among the different breeds (and even among what are probably pariah dogs) than I had originally assumed.
The timing of this could not have been better, too, because at least one type of albinism (or extreme dilution, if you prefer) in dogs was identified in just the last few months. The particulars of that mutation will be especially interesting to horse color researchers, but it merits a separate post. In the meantime, I have set up a new Pinterest board with a wide range of images of albino dogs. I tried to pick ones that showed the range of color in the eyes and the fur. As with the other Pinterest boards, I have tried to be sure to link the pins back to their original site to preserve the photographic credits. In the case of some of these pins, following those links will take you to further information and more photos.