COAT COLOUR WITH GENETIC BACKGROUND OF THE ICELANDIC SHEEPDOG Bernard Vortman MD PhD, Louwke Mandema BSB and Wilma Roem DSB (members of the Dutch Icelandic Sheepdog Association)
Summary Coat colour and pattern of the Icelandic sheepdog are described in connection with its genetic background. A proposal is made for properly naming the coat colour. Since the first coat of a pup is sometimes difficult to interpret, a guideline is given.
All haircolours in dogs are derived from three basic colours: black, red and white. This is caused by two pigments: black pigment “eumelanin”, which shows a black or dark brown colour, and red pigment “phaeomelanin”, which gives a red or yellow colour. White hairs are seen when both pigments are lacking.
The distribution of pigments is regulated by several genes. Every gene in a dog consists of two alleles; one received from the father (male dog), and one from the mother (bitch). So heredity determines which colours the dog has.
photo 1: black and red tricolour
Many Icelandic sheepdogs have a reddish brown colour. Responsible for this is the red pigment. The amount of this red pigment determines the intensity of that red colour. Hence, red can range from pale-yellow, through orange to light-red, deep-red to dark rusty-red. This is caused by the amount of red pigment in each hair and, more important, by the lack of black pigment. If there is very little red pigment present, it is said that there is “dilution” of red pigment.
Black as the main colour is very common in Icelandic sheepdogs. Responsible for this is black pigment. Distribution of black hairs over the dog varies from a few black hairs to complete black dogs. Brown (also called liver or chocolate) is a dilution of the black pigment.
For this reason a brown dog has a brown nose and footpads, and slightly paler coloured eyes than a black dog.
In areas where the black pigment is lacking, red pigment becomes visible.
You can see this in the “black-and-tan” dog: black and red. In this case the red colour is visible in typical areas: the muzzle, legs, above the eyes and under the tail (photo 1). Brown-and-tan Icelandic sheepdogs are rarely seen
(photo 2). They have brown in the same areas as the black colour in the black-and-tan dogs.
photo 2: brown and red tricolour
Hairs are white if both pigments are absent. It is possible that a dog has no white at all, but in most dogs you will see white feet, a white tailtip, blaze, collar or a white line or spot on the breast. If white predominates, we call this piebald (photo 3, 11 and 13). White should not be totally predominant.
photo 3: black piebald
So far we have spoken about coats with one-coloured hairs. The natural coat of the dog (and of many other animals) has banded hairs: one hair has one of more bands of black, yellow and/or white. Agouti, the coatcolour of the wolf, looks like a pattern of shades of grey. Islandic sheepdogs do not have an agouti colour at all.
If we look closely at the red hairs of the Icelandic sheepdog, we will see that these hairs are also banded: a broad band of red colour with a black point, and at the base near the skin a more lighter coloured part, almost yellow. In addition we see between these red hairs with black tips also completely black hairs. This coat is called “sable”.
If we open the upper part of the coat, it is seen that the coat colour near the skin is lighter. This is caused by the yellowish colours of the basic part of the hair. The coat of the Islandic sheepdog shows often alternating bright and dark sections which gives an agouti impression. We can also see that the red on the back is much darker than the red on the breast, belly and limbs.
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