Azawakh Coat Color Genetics

November 25, 2008

Or Why the Color Section of the FCI Standard is Indefensible

“Color: Fawn with flecking limited to the extremities. All shades are admitted from clear sand to dark red. The head may or may not have a black mask and the list is very inconsistent. The coat includes a white bib and a white brush at the tip of the tail. Each of the four limbs must have compulsorily a white ‘stocking’, at least in the shape of tracing on the foot. Black brindles are allowed.”

There are a number of known genetic loci (places) that control coat color in dogs. What we know about the genetics of coat coloration cannot be reconciled with the FCI color standard.

Sable Base Color

Azawakh have a base color of sable, also called red by many people. There are two main loci that control blackness or the lack thereof. The dominant black gene is at the K locus, which also controls brindling.

  • K – dominant black
  • k – recessive, allows the A locus to control base color
  • k(br) – k(br) is the brindle gene. k(br) is recessive to K but dominant over k.

Black dogs are almost unknown in the Sahel. Selection works very well at removing dominant traits and we know there is a strong cultural bias against black animals because animist tradition teaches they are evil. Also the desert climate may exert strong selection pressure against K. The dominant black gene almost certainly does not exist in the Azawakh population.

Because K is not present, the base coat color of Azawakh is controlled by the Agouti locus. Agouti is largely about controlling the production and timing of black eumelanin pigment in the coat. When coat does not produce much eumalanin it allows us to see the inherent red, phaemlelanin, in the coat. There are five Agouti alleles.

  • A(y) – sable red
  • a(w) – agouti (grizzle)
  • a(s) – black saddle or mantle
  • a(t) – black with red extremities
  • a – recessive black

In the Agouti series, the dominant allele is A(y) which is the basic red Azawakh. However, I believe that all 5 alleles exist in the general population. The a(t) and a alleles are rare because puppies that are black or mostly black would be culled, but because they are recessive it is difficult to remove them from the population entirely.

The “chinchilla” or C locus controls dilution of the red pigment, phaemlelanin. There are 4 alleles:

  • C – dominant, normal red pigment
  • c(ch) – chinchilla (yellow)
  • c(e) – extreme chinchilla (lighter yellow)
  • c(P) – Platinum (ivory)

The C locus is not very well understood. It is clear that the intensity of redness is controlled in recessive red dogs, like Azawakh, is controlled by the C locus. The C locus is thought to be a location of co-dominance, meaning that the recessive genes partially express when present. Different combinations of alleles from the C locus allow a range of redness from redk like an Irish Setter, to ivory, like a Samoyed. Clear sand is not specific, but it sounds like a very light yellow perhaps from a combination like c(e)c(P) or c(ch)c(P). If c(P) exists in order to create the “clear sand” color combination then c(P)c(P) is also possible, if rare. That dog would be pure white. How can one recessive combination of genes be allowed but another one is forbidden?

White Extremities

With the exception of whiteness due to red dilution at the C locus, white develops from the extremities. The locus that controls the “height” of whiteness is S, spotting. The dominant allele is S which is no white. Like the C locus, S is an example of incomplete or co-dominance.

  • S – no white
  • s(t) – Trim. Very small amounts of white on the tips of the toes and tail tip.
  • s(i) – Irish pattern (like a border collie)
  • s(p) – particolor pattern
  • s(w) – extreme particolor (linked with deafness)

There is a huge problem with the standard in that it calls for an unstable color pattern. It requires either a heterozygous dog that carries one irish pattern gene or just random luck during development.

The most dominant allele is S, which is no white. However, dogs that are homozygous S (SS) can still often express a phenotype with a white bib and a trace of white on their toes and the tip of their tails. This white expression has no genetic basis! It is just a residual white pattern caused by pigment cells not spreading fully to the extremities during fetal development.

The classic white socks and bib pattern is probably requires heterozygosity in the form of s(t)s(i) or perhaps Ss(p) because if you have s(i)s(i) then you’ll have a classic Irish marked dog with a white collar which is now forbidden in France.

Think about this for a minute. Let’s say we have two dogs with just the right white socks and no collar marking. They are both Ss(i). First of all, it’s just luck that they don’t have a significant white spot on the neck but more importantly, their color pattern isn’t stable when crossed. 1/4 of the puppies will be s(i)s(i), one quarter will be SS and half will be Ss(i). Because of the residual white effect, some of the SS puppies may well be within the standard. Dogs that are s(i)s(i) may also fall within the norms and not have a white spot on the neck just by luck.

A standard that asks for white on the extremities but tries to avoid an Irish marked pattern is indefensible genetically. Also, eliminating the non-white SS dogs from the breeding population will tend to select for homozygous recessive Irish marked, s(i)s(i). That’s exactly the pattern we see playing out. The dogs in Europe are becoming more consistently Irish marked.

Ticking

The dominant ticking gene, T , is also clearly present.

  • T – ticking
  • t – no ticking.

The ticking gene is dominant over non-ticking. Ticking or roaning is small spots of the base color on white areas. Ticking usually expresses on legs, muzzle and chest.  I have heard that in Europe some consider this “dirty markings” and select against it, but why? The oldest examples of Azawakh and many champion Azawakh had ticking in their white. Most Azawakh have small red “freckles” in their chests and socks.

Etc.

There are also dilution genes which can yield blue brindle and have some other effects, but since this is already too long I’ll save that for another post.

A Modest Rewrite

The color standard should be changed to match the reality of the genetics in the native population. I’d recommend something along these lines:

Color: The base coat colors are forms of sable ranging from ivory to red and may be grizzled. Brindle markings may be present. Mask may be present. Mantle or saddle may be present. White on the extremities, with or without ticking, may be present including Irish marked and particolor patterns. Black markings may occur in the dilute blue form.

Eliminating Faults: …

  • Absence of any white marking at the extremity of one or more limbs.
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3 Responses to “Azawakh Coat Color Genetics”


  1. […] Last timeI took a spin through coat color genetics in dogs and tool a look at some of the things in the Azawakh standard that don’t fit. I left out some finer points of discussion involving genes that convert black pigments to  brown and/or blue. […]


  2. […] 6, 2008 There have been quite a few hits on my ravings over Azawakh color genetics. Seems a popular topic, so here are some more in-depth resources on dog coat color […]

  3. Shelton Says:

    Incredible. sahelhound.com is great.


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