More Azawakh Color Genetics

November 26, 2008

Or Yet More Wrong Rules in the FCI Standard

Last time, I 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.

Let’s start things off with some quotations from the FCI Azawakh standard and then we’ll take a look at whether they make any sense.

 
Nose: Nostrils are well opened. The nose is either black or brown.
Eyes: Almond shaped, quite large. Their color is dark or amber. Eyelids are pigmented.
Coat: … Black brindles are allowed.
Eliminating Faults: …

  • Light eye: i.e., bird of prey eyes

Although these are color rules in the FCI Azawakh standard are outside of the discussion of the coat, the loci that control these traits also affects coat color.

The Liver Locus, B

  • B – normal black
  • b – black pigmentation converted to brown

The default color for noses in dogs is black. Brown noses are controlled by the the B or Liver locus. The recessive allele of this locus affects the production of eumalanin, converting all black in the coat to brown (aka liver). Saddles, shading, brindling and nose pigmentation are all converted from black to brown. Recessive B (bb) also causes amber eyes. When liver is expressed, anywhere there is black in the body of the dog it is converted to brown. It is impossible for a bb dog to have black anywhere in its coat.

Recall that brindle is controlled by the K or black locus. The dominant black K gene does not occur in Azawakh but the semi-dominant k(br) allele does occur as well as the k, non-black, allele. Any dog that has a k(br) gene will be black brindled, but if it also has recessive bb, then the bridling will be dark brown.

The amendment that added brindling contains a mistake. At the very least, it must be changed to allow black or brown brindling.

The Dilution Locus, D

ABIS has surveyed a few blue Azawakh in the Sahel and there have rarely been blue Azawakh born in the West.  This can be expressed as either blue brindling or blue mask or both. Blue is controlled by the D locus.

  • D – normal pigmentation
  • d – dilute pigmentation

The recessive d allele primarily affects the production of eumalanin pigment, causing it to shift from black to blue. It also has a slight effect on red phaeomelanin pigment causing it to be less red.

The D locus can interact with the B locus. If a dog is both recessive liver (bb)  and recessive blue (bb), then it will have Isablella black. Weimeraner’s are isabella colored.

Blue causes amber eyes.

Blue also affects nose pigmentation. In a blue dog, the nose cannot be black, it will be blue. In an Isabella dog, the nose is isabella which looks like brown with some blue tattooing.

Amber But Not Light Eyes?

I cannot understand what the difference is between amber and light eyes.  Very light eyes occur in isabella dogs which must be both recessive for B and recessive for D, an excruciatingly rare combination in Azawakh. Most likely amber is caused by the expression of recessive B (liver). In a liver dog, there is no genetic difference between a dark amber and a lighter amber. These are just chance differences in development of pigment producing cells. Both are caused by the bb combination, which is allowed. Also, how light is light? When does amber become “bird of prey”? How many angels can dance on the head of a pin?

The light eye eliminating fault prohibition should be stricken.

A Re-Rewrite

Last time, I made a whack at rewriting the coat color rules. I mostly left out the discussion of dilution and brown loci. I need to update my rewrite to account for those loci.


Nose: Nostrils are well opened. The nose is black, brown, blue or isabella (blue + brown).
Eyes: Almond shaped, quite large. Eye color is any shade of brown or amber. Eyelids are pigmented.

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 liver brown form, the dilute blue form or the combination blue + brown (isabella) form.

Eliminating Faults: …

  • Light eye: i.e., bird of prey eyes
  • Absence of any white marking at the extremity of one or more limbs.
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6 Responses to “More Azawakh Color Genetics”

  1. Mimi Drake Says:

    There is no text standard, however precisely wordsmithed, that can ever adequately capture the essence of the idi – or of a dog of any race, for that matter. Even an illustrated standard will merely reduce the being into some two dimensional, geometric form.

    Breeding is both a science and an art. The science can be studied and even learned, but the art – unlikely. One breeder will paint like Picasso, another like Míro, a third – like Bart Simpson.

    The perception, the eye, is an innate ability. One either has it, or one does not. Those who see eye to eye – *usually* have some commonality of aesthetic sense. Then there are those who won’t ever “see it”, even if they memorize each and every word of that well crafted “breed standard” and attempt to visualize a creation from it.

    To me, the value of a “breed standard” is an exercise of frustration. Although both my academic background in biochemistry and my advance degree in immunology instilled disciplined thought processes in me, they never did help my breeding results until I learned to trust my eye and my intuition. So the anarchist in me was born afterwards.

    Color is cosmetic. The study of color genetics at one time fascinated and consumed my interest. Now that too has passed. Head, expression, structure – they still intrigue me.

    Sorry to butt in like this.

  2. Brian Reiter Says:

    The Azawakh standard is full of logical inconsistencies. Part of the problem is the whole idea of a standard is based on a faulty premise that function follows form. The truth is that it works the other way round and the most important features of an animal are not visible in a show ring.

    My main point with these two articles was to pick an area where there is some good science (color genetics) and show how there is no correlation between reality and the rules in the standard. The standard is important because in Europe people are required to breed to the standard and win points in shows or they cannot get permission to breed.

    Perhaps a better rewrite would be to eliminate color as a breeding point. I suspect the reasons for the existing color combination rules is political and about attempting to visually distinguish Azawakh from Sloughi.

    Re-Rewrite Redux

    Color: Any combination of colors is acceptable.

  3. Mimi Drake Says:

    Y-ay, there you’ve got it!!

  4. Jess Says:

    I am quite firmly convinced that the frequent prohibition in breed standards against light eyes is due to the fact that dogs with a light eye color look more predatory, like wolves. Light eyes are creepy, they remind us of predators. Can’t have that, can we?


  5. […] 1, 2008 Previously, I wrote about the color rules in the FCI standard for the Azawakh breed. The FCI or Fédération […]


  6. Hey, nice tips. I’ll buy a bottle of beer to that man from that forum who told me to go to your blog 🙂


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