Black (the "K" influence)

As we have established that all dogs are genotypically black, we now have the basis for our coat foundation.
What does a black dog look like? Well, that's obvious, isn't it. The above dog is a dominant black. Now, take note of some important black factors.
The nose is black, as shown in the photo left. In normal black, the nose, skin, coat and eyerim colour is black. Allow, of course for possible sun bleaching of the coat, but basically this is an all-black dog. (This is without the possibility of white or tanpoints, etc.)
The black factors expressed here also affect eye colour. Black is the basis for every form of eye colour, regardless of if it is an instance of normal black pigment (dark eyes) to pigmentally reduced coloured dogs (which results in lighter eyes, such as amber.) Note the eye in the photo to the left. The eyerim is distinctly dark, and the eye itself is a dark shade of brown. No pink or white (lack of pigment) can be seen in either instances of eyerim or nose.

Our phenotype of this supposed 'black' dog is "a^t  a^t BB DD EE KK SS mm tt". We will now look at how these alleles affect our current dog, case #1. Black is allocated to the loci "K". This is important to remember. "K" can be found either in the middle of, or in some cases, at the beginning of the genotype sequence. This is due to the fact that 'black overrides all colours.' Any upper case "K" found in the phenotype indicates dominant black and this works alongside any patterns of 'Irish Ticking/whiting' that can be seen. Any lower case "k" does not mean black is hidden, but rather that now there is an opening for expression of the agouti patterning. I will touch on this much further along. Remember, black is "KK", "Kk", and "kk'. 


Now I will include photos as examples of black colouration in dogs. These dogs actually all express a variety of patterns which is affected by the agouti gene. The point I am trying to make here is the presence (the visible presence) of black in dog colouration.

Black with Tan Points (called Rust red in this breed) as seen on a Rottweiler. The dog is predominantly black. In addition to the agouti markings, this dog is dominantly black. It is not, however, "KK". This is because the black is expressed on the "E" "B" and "D" alleles. These will be discussed later. This dog's phenotype is actually "kk"  - as it must be to express tan points.

Black with Tan Points (also Rust) is shown here added with white. This patterning is also a result of the agouti alleles, however the white 'spotting' seen is not. White will be further discussed in another topic, as it is a result of a completely different sequence.
This dog is predominantly black, as the Rottie above - it merely includes the presence of white.

Black and White with white spotting pattern - this is probably a better example of predominantly black dogs with other patterning. This dog differs to the above two, in its "K" sequencing. As this dog is a dominantly expressed 'Black and white' and no agouti combinations are present, its genotype is more likely than not "KK". Another possibility here is for this dog's phenotype to be "Kk". The reason for lowercase here is that tanpointed Border Collies are "kk", and occur fairly regularly. Therefore this dog could be either.

These are simply dominant expressions of the colour black on the "K" influence. Black affects almost the entire range of allele pairs.