GRANADAN MINIATURE DACHSHUNDS

INCOMPLETE - will finish ASAP.

The prediction and understanding of colour and pattern in our lovely breed has long been a source of great interest. It is imperative for anyone interested in the production of healthy dogs to at least strive to know a very little of accurate colour and pattern genetics, as health is intrinsically tied into the genes and can be affected by some patterns and colours. Once a few basic rules are understood, it is not such a complicated undertaking as may be thought.

For colour, as with every other trait, a dog inherits one gene from the Sire and one from the Dam.

Genes for different traits have a place on the chromosome called a locus. For example, the A locus controls the agouti factor, the B locus controls the black, the E locus controls the extent of black, the C locus controls the intensity of red based pigments. The colours and patterns we see are the result of the combinations at these loci.

Colour is the colour of the dog.

A pattern is the effect of a gene upon those colours to alter the placement and appearance of them.

Dachshunds have two pigments (melanins). Eumelanin (yoo-mell-a-nin) which is black pigment, and Phaemelanin (Fay-mel-a-nin), or red pigment.

All the wonderful array of Dachshunds we see are the product of these two pigments and genes working on them.

The effect of these pigments can be altered. Eumelanin is black when the B locus is BB or Bb. If the dog is bb the black pigment is lightened to chocolate. Black (B) is dominant to chocolate(b). Or to put it the other way, chocolate (b) is recessive to black (B)

Why bother?...

Every puppy recieves one gene for it's colour from each parent.  If a male is Bb at the B locus, he can throw either the B or the b to his offspring.  If the female is the same, the combinations for the puppy could be BB Bb or bb.  If that puppy is bb (for examples sake), it will be chocolate based.  The rest however depends on what is present at A.  If this puppy is AyAy or Ayat it will be red - but with all the black turned to chocolate - chocolate ticking (shading), chocolate nose, chocolate eye rims, lighter eyes, chocolate toenails.  If it is atat at the A locus however, it will be chocolate and tan.  If this puppy has inherited chch at C, then the red pigments will be changed to cream on the tanpoints and puppy will now be chocolate and cream.

So this chocolate and cream puppy is atat bb chch.  It is very easy to code the dogs down and this makes it easier to predict what may be produced from any pairing.  If this dog is mated to a homozygous red, the results would be different to what we would get if we mated it to a red carrying tanpoint or a homozygous red carrying chocolate (Bb).  Two would produce acceptably coloured puppies, the other may produce chocolate based reds in the litter.  So we can see why knowing and being able to write it down is useful to us.

We can manipulate these codes to produce the colours we want, and to avoid the combinations we do not want.

Chocolate based red.  This colour is not in the UK breed standard. 

This genotype may explain the origin of the myth that mating red to red leads to loss of pigment.

Red.

The red Dachshund is genetically Ay sable, or red with black ticking. The amount of black ticking varies from very lightly marked dogs, often with just dark tipping around the eyes and the edges of the ears and/or tail, to far more heavily shaded individuals.

It is not true that all reds carrying tanpoint are shaded as shown by this red bitch sired by a black and tan.

Tanpoint.  (black and tan/chocolate and tan)

Tanpoint (at) restricts red pigment to the face, feet, chest, underside of the tail, vent and eyebrows.  The rest of the dog is covered by the eumelanin (black based) pigment.

at is recessive to Ay. A dog who is Ayat will be red, carrying black and tan as the Ay is dominant to the at.  A tanpoint dog cannot carry Ay sable (red).

Whether the atat dog is chocolate or black based, again depends on the result at the B locus.

At the e locus are the genes which control "how much" black (eumelanin) pigment to allow in the coat. An EE dog has the full amount of black, so does an Ee dog. But the dog who is ee (or homozygous for non extension of black) will not have a single black hair. At birth they will have grey/pink nails and noses, and as adults may have nose pigment which fades in winter. In the past it has been wrongly stated that these dogs are created by repeatedly mating red to red. But it can be seen that the ee dog may in fact be genetically a black and tan with no black pigment extended into the coat.

Opinions vary. Some say a clear red is a minimally ticked homozygous red. However there are reds sired by black and tans who only exhibit a minor amount of ticking on their tail who are independently described by very experienced judges and breeders as "clear" reds. It would seem a dog should be termed a clear red from its genotype and not it's phenotype. The genotype for a dog 'cleared' of black would be an e red.

The red nosed red is a normal AyAy (homozygous red) or Ayat (red carrying tanpoint) red dog that is bb at the B locus. This has the effect of turning all black pigment to chocolate. So the dog has the liver nose and lighter eye of the chocolate on a red coat. Any ticking that would be on a red hair is also turned to chocolate. Again, this is not caused by mating red to red, but by pairing the gene for red with homozygous b to cause black pigment to be altered to chocolate.