It is generally known that the Icelandic sheep is one of the most colourful breeds of sheep in the world. However, not many people are familiar with how these colour variations manifest themselves. In the years that I have been breeding Icelandic sheep I have become increasingly fascinated with their wonderful colours and one of my aims in life is to breed as many of the variations in appearance as I will have time to. As most of you already know, there are basically three factors that determine the appearance of a sheep. Technically these are referred to as existing at the A, B, and S loci of the colour genes.
Several patterns exist in sheep in general but usually in each breed there is only one pattern.
The Pattern Factor in the Icelandic breed has six forms, the Colour Factor has two forms and the Spotted Factor also has two forms. Technically these forms are called alleles. I will explain each factor and its forms in turn. That is, colour inhibited or expresses on the various parts of the body. Inhibition of colour is dominant over expression.