DARPG Guide to PWD Genetics

Very work in progress guide to Portuguese Water Dog color genetics

- much of this also works for poodles, but i may make a poodle guide down the line

All art done by me

Disclaimer:

I am simply a fan of the breed and all of this information is strictly from my own research, I can not confirm with absolute certainty that this is all 100% correct. There is not a lot of info out there about PWD genetics so this is my best attempt at compiling all that I've found.

This guide is designed for DARPG purposes, not irl dog breeding. For more info on general dog color genetics please check out http://doggenetics.co.uk/. Its a great guide and where I've confirmed most of my info.

PWD BASE COLORS:

K Locus (Black)

(Kb) Dominant Black- Dominant black is the most common base color in PWD. 'Kb' will mask everything on the A locus. Because black is dominant, a dog with even just one KB gene will be solid black.

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B Locus (Brown)

(b) Liver (Brown) - In PWDs liver is usually just called "brown". In order for a dog to be born liver, the dog has to have two copies of the recessive b gene (bb). The liver gene changes all black based pigment to brown, including patterns like brindle. A liver dog's skin pigment including the nose, lips, and pads will also be affected and can be anywhere from a chocolate to a pink in color, and their eyes are a light amber or hazel rather than brown.

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E Locus (White)

white - preferred shade (left), cream (right)

(ee) Recessive Red (White) - Any dog that is 'ee' will be solid white, (with the exception of white markings) as the 'ee' gene masks the other pigment types and markings (black or liver). A dog that is EE or Ee will not be visually white. In PWD white dogs should have black skin pigment, a white dog with liver pigment is undesirable (bb). Recessive red PWDs present as white or very pale shades of cream, although cream shades are rarer and only found outside of the U.S

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(i) Intensity -The I locus is a gene that affects the intensity of red pigment, so in PWDs this influences the shade of white (recessive red) a dog is. For this gene I refers to darker pigment and i refers to lighter. A II dog would be a rich dark red (think irish setter), while ii dogs appear white or very pale cream. Ii dogs are a middle ground, normally in shades of gold/yellow. PWDs have only visually appeared in shades of white and cream so they should all be ii.

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G Locus (Greying)

GG - beige (left)      Gg - light brown (right)

(G) Progressive Greying (Greying Brown) - The greying gene occurs on the G locus and is incredibly common in brown (liver) PWD lines. Greying black based dogs will be mentioned further down. It's thought to be an incomplete dominant, so G is greying and g is non-greying, and in order for a dog to express greying it only needs to have one copy of G (so its genotype can be Gg or GG). GG will generally have a stronger effect on the coat than Gg. A dog that doesn't express the greying gene has the genotype gg.

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STANDARD MARKINGS:

S Locus (White Markings)

black (left), liver (middle), greying liver (right)

(S) Solid or residual white -  In PWDs solid is most common, and most dominant, but residual white is also very common. Residual white is a very small amount of white on the chest, toes or tail may occur when the pigment doesn't migrate fully as the embryo develops. Mostly one color (black or brown) with minimal markings (less then 5%).

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Ssi - black irish (left), liver irish (middle), greying liver irish (right)

sisi - black heavy irish (left), liver heavy irish (middle), greying liver heavy irish (right)

(si) Irish & Heavy Irish -  Irish is typically restricted to the muzzle, legs, tail, and belly. Dogs with even one copy of si will shown white markings. PWD with flashier irish markings are referred to as "Heavy" irish, these dogs have two copies of si (sisi). Heavy irish will have a full or partial white collar separating a colored head from a colored body.

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black (left), liver (middle), greying liver (right)

(sisp) Irish Parti- Some dogs may have one copy of irish and one of piebald (parti-color), in PWDs this doesn't necessary have a name, these dogs are phenotypically lumped in with other parti dogs. The combination is usually characterized by irish type markings with more irregular white patches along the stomach, head, and back.

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black (left), liver (middle), greying liver (right)

(sp) Parti-color (Piebald) - A Parti Color PWD is often referred to as having more white then black or brown.  it can be a pretty even 50/50  or extreme where the majority of the dog is white with small black or brown markings. A dog must have 2 copies of parti (spsp) to be visually piebald.

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T Locus (White Marking Modifiers)

On top of the various white markings Portuguese Water Dogs can present, there is also a variety of mottling and ticking that pops up in the breed as well. This spotting will appear as whatever color the dog is under their white markings, so liver dogs will have liver ticking and black dogs - black ticking.

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 Tt - greying liver ticked (left), liver ticked (middle), black ticked (right)

TT - greying liver heavy ticked (left), liver heavy ticked (middle), black heavy ticked (right)

(T) Ticking - Ticking refers to the presence of flecks or spots of color on the white areas of the coat. Ticking is expressed on any white area, as long as the white is 'real' white ( i.e. not recessive red (white). The color of ticking/roan corresponds to a dogs base color (black or liver). Ticking amount varies greatly between dogs, and this can be partly explained by the idea of incomplete dominance. If the ticking gene (T) displays incomplete dominance over the clear white gene (t), then a TT dog would have heavy ticking and a Tt dog would have lighter ticking.

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silver fox (left), brown fox (middle & right)

(Tr) Fox (Roan) - Roan is a rarer but standard pattern in PWDs, but within the breed it is called "Fox". A dog is called silver fox if they are black based or brown fox if liver based. Roan is pattern that produces heavily mottled white areas. Often only a small amount of scattered white is visible. It is believed to be part of the T series (ticking).

OUT OF STANDARD COLORS:

These are colors that are not within the Portuguese Water Dog standard, but can naturally be found within the breed.

All of these colors/patterns would need to be shown in Color Club Classes for Pedigree-Club shows

G Locus (Greying)

GG - light grey (left)      Gg - grey (right)

(G) Progressive Greying  (Grey) -   A greying black is not mentioned in the breed standard but is considered undesirable and "poor pigment". Greying black dogs often appear to have a blue tint to them, but still have black skin pigment (dark eyes, nose, pads), this is the same gene that creates blue poodles. These dogs are not dilute (dd).

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K Locus (Black)

black based brindle (left), liver based brindle (right)

(kbr) Brindle - In most breeds brindle typically appears as black stripes on a red base. In PWD is often almost looks like red stripes on a black dog, sometimes only visible on the muzzle and hind legs when shaved. Brindle (kbr) is dominant over ky but subordinate to Kb. A Kbkbr dog will not be brindle. A kbrky or kbrkbr dog will also display whatever it has on its A locus, but any phaeomelanin in the coat will be brindled (example: brindle points).

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(ky) Non-black - recessive non-black (will still have black nose pigment and may have black markings, but may also have red markings too). Sometimes referred to as simply k. A kyky dog will display whatever it has on its A locus (sable, tan points).

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A Locus

black based sable shown

(Ay) Sable * - Visual sables are incredibly rare in the breed, especially since the majority of PWD are dominant black (Kb). It only takes one Ay for a dog to display sable as it is the most dominant in the A series. Thus, a dog may be an combination of (Ay --) and still be born a sable. A dog's sable will be whatever colour is displayed by the K or B genes.

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black based tan-pointed (left), liver based tan-pointed (right)

(at) Tan Point- Two copies of the tan point gene must be present in order for a dog to express it. Every tricolour and tan point dog will be genetically (atat). A dog that is (-- at) will not be tan point. Commonly pointed PWDs appear to have a melanistic mask, covering a portion of their points on on the face.

FULL GENOTYPE EXAMPLES:

Ok so now you know how the genes work individually but why don't we look at some full genotype examples together?

Example #1

AyAy Bb Ee gg ii KyKy sisp Tt

This dog is a sable irish parti with light ticking, it also carries for white (Ee ii) and liver. The dog is also non greying (gg)