Because very pale cream or even white individuals occur it is probable that the C/ch type of pigment reduction is also found in this breed. The gene d for blue dilution has been recorded but is not frequently seen.

One can readily realise that the different combinations of these various colour and pattern Genes produce such a varied group of colour types that the Breed Standard does not attempt
to define or describe them.
 

                                THE GENES IN CHIHUAHUAS for colour are as follows.
 
 

                                                As      B        C       D      E       G       m       S         t

                                                   y     b      Cch    d      ebr    g                  si

                                                 at                                                                 sp

                                                                                                                      sw
 
 

A/s allows the distribution of DARK pigment over the whole body surface (Newfoundlands & Chesapeake Bay Retriever).

ay restricts markedly the areas of DARK pigment and in its most complete expression produces a clear sable or tan coloured dog (Basenji & Irish setter).

at produces the bicolour varieties, black & tan, liver & tan etc. All of these are described as tan-points (Dobermans & Welsh Terrier)

B produces black coat colour determined by a certain quantity and quality of dark pigment granules in both the cortex and medulla of the hair.

b allows the reduced degree of pigment formation observed in the chocolate brown (liver) series of dogs.

C allows full depth of pigmentation. This can be seen deep red and dark tan, deep rich pigmentation of golden bundles or deep absolutely black or liver varieties.

Cch or chinchilla gene has a distinctly greater effect in reducing the red-yellow pigment. for this reason it becomes apparent chiefly, if not entirely, in light-pigmented areas. the Schnauzer is a good example, where there is dark pigment still plentiful but the yellow has been so reduced as to be almost if not entirely absent.

D this gene is called intense or dense pigment most dogs fall into this group. The actual colour can be various but must be very intense.

d produces blue dilution most clearly seen in short haired dogs such as blue Great Danes, Blue Greyhounds, or blue Dobermans. In longhaired breeds, it is seen in Chow Chows and Poodles.

Em produces the black mask pattern as in Pugs and many other breeds and is now given the top ranking over all other E members.

E allows the formation of dark (black or brown) pigment evenly over the whole coat.

ebr produces brindle

G is responsible for lightening puppies born dark it can easily be confused with the gene d.

g however is applied to dogs that remain without this lightening gene, therefore they would be born grey or pale rather than born dark and fading later. In the same way as Silver Poodles and Kerry Blue Terriers.

m shows uniform pigment.

S is responsible for solid colour coats with no white or perhaps very minute spots of the toes or chest.

si called Irish Spotting as it was first noted in the Irish rat. In these animals the following areas may be white: muzzle, forehead, feet, tail tip, chest, belly, throat, neck eg. Basenjis.

sp responsible for piebald spotting these can resemble Irish spotting at one end of the scale to animals which have only 15 to 20% of the coat pigmented (Beagles)

sw causes extreme piebald spotting these can resemble where the dog is mostly white with just one or more small patches of pigment say on an eye, ear, tail, or rump.

t produces animals with clear white coats with no ticking (flecks) of colour on the white areas, which may be large or small.