Why are Samoyeds all White?

Have you ever wondered why Samoyeds only come in white? What makes them white? Where does the biscuit come from? Understanding canine genetics is a work in progress, but we have discovered enough of the puzzle pieces to get a decent idea of our answer.

Obligatory disclaimer- I am not a geneticist; I’m just a nerd with a dog. If you see something off, please reach out to me and I will fix it. To the best of my knowledge, everything below is factual. I have several theories that build on what is stated here but those will be in a future post.

Some Background Info

There are a handful of theories floating around on why Samoyeds are white. Some say it’s the combination of being both recessive red and recessive black. Some say they’re just one big white spot. There is a little bit of truth to all of them but none are quite correct. It’s even a bit confusing because some testing companies appear to report them as being “Dominant Black” or other colors.

All Samoyeds are Recessive Red

Think of a locus as a specific location on the DNA strand. Each location can hold two alleles, or genes. Alleles are given names based on what locus they appear at. For example, all Extension locus alleles use E’s. Capital letters indicate dominant genes, while lowercase letters indicate recessives. e is the most recessive allele on the E locus, which means dogs need two copies of e (notated as e/e) to appear white/cream/red and cannot hide or carry any other alleles on this locus. There are a handful of alleles on the E locus, but to understand Samoyed white we only need to know two- e recessive red, and E dominant color. Dogs with two copies of E (E/E) or one copy of each (E/e) will have their final color determined by other genes on other loci and will not be white/cream/red.

Genetically, Samoyeds are white because they are e/e recessive red. They are also mostly piebald, but that isn’t the main source of their color so we will come back to that in a second. You might be thinking “Recessive Red? What? They’re clearly WHITE.” You are correct. The recessive red allele stops the coat from producing Eumelanin (black, brown, blue, or lilac pigment) so the coat is entirely colored by Pheomelanin. Pheomelanin is most identifiable as the tan areas on a tan-point dog. Pheomelanin does not have to be tan, it can range from pure white to yellow to a deep red. It is distinctly different from the brown of a brown dog and is responsible for the coloring of Samoyeds, Golden Retrievers, and Irish Setters. There is an infinite number of shades between white and red; I have illustrated 5 below.

The color of an e/e dog is thought to be determined by another set of genes, labeled Intensity genes or sometimes referred to as the I Locus. These intensity genes are only loosely understood thus far; a study has identified a handful of genes that relate to intensity but the results are not consistent across all dogs and are overall pretty vague. Embark now offers a linkage test for intensity that samples five different genes to give an intensity prediction, you can read more about it and how it works here. The three lightest shades above would all come back as “Dilute Red Pigmentation,” so it isn’t super helpful if you were hoping for a “how biscuit is my Samoyed” test, but maybe one day we will get there.

Let’s Take a Detour

For a more illustrative real-world example (and proof that we can breed for shades of e/e), we can look at Golden Retrievers. All Goldens are e/e just like Samoyeds, but their gene pool contains all of the intensity variants, and their coats aren’t obscured by white spotting, so it’s easy to see the entire Pheomelanin spectrum. From studying Goldens, breeders observed that more intense shades of Pheomelanin seem to be dominant over less intense shades of Pheomelanin. This is noteworthy because it means Samoyeds are likely also fixed for recessive genes when it comes to intensity; so, while you could in theory breed for dogs with more intense pigment, there is likely an upper limit to just how intense it is possible to achieve without adding to the gene pool. More reading on Recessive Red can be found here.

Confusing Results

You may be thinking: But why is my color panel telling me my dog is dominant black?

This is not an error with the test. Some testing companies pick a poor format for displaying results which can lead to confusion like this. The test is correct, your dog is dominant black (or whatever other color it mentions), but the E locus is epistatic to (think “dominant to” but for loci instead of alleles) all other loci except for white spotting (S locus). All dogs have two alleles at every locus, even if expression of one or more of them is hidden by another locus, and all of these hidden loci are still reported on the color panel. You can think of coat color as working in layers; for Samoyeds the base layer is black, covered by recessive red, covered by white spotting.

For a fun look at what colors Samoyeds are hiding under the e/e white, I’ve taken the Embark results of my two Samoyeds and did a breakdown of each locus and what it means here!

Samoyeds are Mostly Piebald White

The other big contributor to the white color of Samoyeds is piebald. Piebald is the most common white spotting gene in dogs. About 85% of Samoyeds have at least one piebald (sp) allele on the S (Spotting) locus, with the majority being homozygous for piebald. S locus has two testable alleles, S solid color (no white) and sp piebald. Spotting genes are fickle though, so predicting white based on genetic results isn’t as straightforward as it is for other genes. S solid color is incompletely dominant, meaning it doesn’t always completely mask any recessive genes it’s paired with, and phenotypes (how a dog actually looks) are somewhat inconsistent even in dogs that test genetically identically. Dogs with two solid alleles (S/S) are solid-colored. Dogs with one copy of piebald (S/sp) can be anywhere from 0-50% covered by white, and dogs with two copies (sp/sp) can be anywhere from 50-100% white.

Piebald white is different from e/e white and will always be a true white because it stops the production of both Pheomelanin and Eumelanin in the skin and the coat- turning the skin pink and the coat white. Piebald white is what gives those puppy bellies their iconic polka-dotted look. It also follows a rough pattern, where white is always added to the extremities first (tail tip, nose, toes) and works its way to the head and tail gland last. The last place to lose pigment on an extreme piebald dog is its ears. I’ve illustrated below some iconic piebald patterns, though this is by no means an exhaustive list. Like shades of recessive red, there is an infinite number of piebald patterns, up to and including completely white dogs.

The majority of Samoyeds have such pale pheomelanin that e/e white and piebald white are indistinguishable from each other. It only becomes obvious the breed is piebald when you happen across a dog with a higher intensity pheomelanin which allows the piebald pattern to be visible. There are a handful of other white spotting genes out there, and Samoyeds may possess those as well but unfortunately, genetic tests for these are unavailable at present so it’s impossible to tell for sure.

Too Long; Didn’t Read

Samoyeds are white thanks to two different genes. On the Extension locus, all Samoyeds are e/e which gives them a color anywhere from pure white to a golden biscuit. On the Spotting locus, most (but not all) Samoyeds are piebald or piebald carriers (sp/sp or S/sp), giving them extra areas of pure white.

Curious about your pup? You can grab an Embark Breed + Health Kit and confirm what you see here for yourself! Send me a message through the Contact page if you have questions or interesting results to share.

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