What’s Behind a Sesame?

One of the most common things I hear about Shiba colors from pet owners (besides I have a fawn/brown Shiba, or I have a tri color as well) is I have a Sesame Shiba. The stranger then proceeds to whip out their cell phone to show me a picture of their red Shiba with black tipped hairs (also known as a Sashige or dirty red). It’s very hard to explain that no sir, your Shiba is not a sesame but instead a sashige without sounding like an ‘elitist snob’.

Even breeders can’t seem to agree what a sesame is – is it a shaded sable? Or is it an agouti? Now if you’re not big into genetics you’re probably like Alexis what the heck? Shibas are red NOT sable, & what the heck is an agouti?!

The Shiba has 2 main alleles for color. (we’re not going to worry about splash for pinto coats) The A locus (agouti) & the E locus (red/yellow).

To quote Paw Print genetics (https://www.pawprintgenetics.com/)

The A locus:

The A Locus (Agouti) coat color test reliably determines if a dog has one of the following genotypes at the A locus:

A^y/A^y	This dog carries two copies of A^y which results in a sable/fawn coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The sable/fawn coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus which allows for agouti gene expression. This dog will pass on A^y to 100% of its offspring. Interpretation: Sable/fawn
A^y/a^w	This dog carries one copy of A^y and one copy of a^w which results in a sable/fawn coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The sable/fawn coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus which allows for agouti gene expression. This dog will pass on A^y to 50% of its offspring and a^w to 50% of its offspring. Interpretation: Sable/fawn (carries wolf sable/gray)
A^y/a^t	This dog carries one copy of A^y and one copy of a^t which results in a sable/fawn coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The sable/fawn coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus which allows for agouti gene expression. This dog will pass on A^y to 50% of its offspring and a^t to 50% of its offspring. Interpretation: Sable/fawn (carries tricolor/black and tan)
a^w/a^w	This dog carries two copies of a^w which results in a “wolf” sable/gray coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The “wolf” sable/gray coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus which allows for agouti gene expression. This dog will pass on a^w to 100% of its offspring. Interpretation: Wolf sable/gray
a^w/a^t	This dog carries one copy of a^w and one copy of a^t which results in a “wolf” sable/gray coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The “wolf” sable/gray coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus which allows for agouti gene expression. This dog will pass on a^w to 50% of its offspring and a^t to 50% of its offspring. Interpretation: Wolf sable/gray (carries tricolor/black and tan)
a^t/a^t	This dog carries two copies of a^t which results in tan points and can also present as a black and tan or tricolor coat color. However, this dog’s coat color is also dependent on the E, K, and B genes. The tan point coat color is only expressed if the dog is also E/E or E/e at the E locus and k^y/k^y at the K locus. This dog will pass on a^t to 100% of its offspring. Interpretation: Tricolor, black and tan

The E locus:

The E locus (Yellow/red) coat color test reliably determines if a dog has one of the following genotypes at the E locus:

E/E

This dog carries two copies of E which allows for the production of black pigment. However, this dog’s coat color is also dependent on the K, A, and B genes. This dog will pass E on to 100% of its offspring.

Interpretation: Black

E/e

This dog carries one copy of E and one copy of e which allows for the production of black pigment. However, this dog’s coat color is also dependent on the K, A, and B genes. This dog will pass E on to 50% of its offspring and e to 50% of its offspring, which can produce a yellow/red coat (including shades of white, cream, yellow, apricot or red) if inherited with another copy of e.

Interpretation: Black (carries yellow/red)

e/e

This dog carries two copies of e which inhibits production of black pigment. The coat color of this dog will be yellow/red (including shades of white, cream, yellow, apricot or red). This dog will pass e on to 100% of its offspring.

So in simple terms a red Shiba (genetically sable) is Ay/ – it can carry black & tan(at) or sesame (aw) or be a “clear red” (Ay/Ay). But there’s something not quite understood (well at this time I wasn’t able to find info on) that an Ay/at dog will have an almost agouti pattern called a shaded sable. Usually you can tell because the dog will have a widow’s peak & probably will not have the black hairs all the way down their legs. So this type of Sesame pattern is hard to breed for because it’s not very predictable like the aw sesames. I’m going to assume the Ay gene has some kind of mutation to it that allows this expression because it has shown up in certain lines. It’s just hard to reliably breed for it.

Now the aw Sesame is a bit easier – its dominate over black & tan but recessive to red. So most breeders who are aiming to produce sesames in a litter will breed sesame to black & tans. Although if you breed an aw/at to Ay/at you have a 25% chance of producing a red Shiba that carries Sesame, a 25% chance of a red Shiba carrying black & tan, 25% chance of a Sesame, and a 25% chance of a black & tan. While a Sesame to black & tan has a 50% chance of sesame puppies.

Now things get more tricky – you have an akagoma (red sesame) & kurogoma (black sesame). The AKC standard states that “Sesame (black-tipped hairs on a rich red background) with urajiro. Tipping is light and even on the body and head with no concentration of black in any area. Sesame areas appear at least one-half red. Sesame may end in a widow’s peak on the forehead, leaving the bridge and sides of the muzzle red. Eye spots and lower legs are also red.” Some people misinterpret the standard stating sesame can only end in a widow’s peak (Ay/at Sesame). The Japanese judges prefer the sesame to run along the bridge of the nose & follow the pattern of a black & tan. (which would make the dog an aw sesame) The Ay/at sesame will always be a red sesame – I have yet to see one that would be considered a black sesame. Now the aw agouti sesame can be a red sesame or black sesame. From what I’ve seen if the Shiba is carrying the cream gene (E/e) they tend to have brighter, flashier urajiro. So a sesame without this cream gene looks darker & can be considered a black sesame. Another thing to keep in mind is the coat will change when a dog is shedding (like a black & tan) or if the lighting is hitting the dog at a certain angle, which can make a dog appear redder or blacker. Per AKC registration we can only register a sesame as a red sesame. NIPPO has red sesame & black sesame as a registration choice though.

Maybe another question you may have is why don’t we just breed sesame to sesame to get aw/aw Shibas? The Japanese say not to breed a sesame to a sesame because you’ll get incorrect coat color – the dog will be too dark to be a correct sesame per standard.