There are 2 basic coat colors in Shelties, sable and black. Each dog carries 2 genes for color. Sable is dominant over both tricolor and bi-black. Any dog that has a sable gene, will be a sable, regardless of what other color gene it carries. A sable can be a wide range of shades, from golden brown or red to dark brown with heavy black shading.
Some people erroneously think that a sable with black shading is a tricolor.
If a dog's predominant coat color is brown or red, it is a sable, regardless of how much black overlay the coat exhibits. The merle gene is a color modifier that acts on the basic coat color and produces a mottled pattern and can also produce blue eyes. This gene is in addition to the 2 color genes that each dog carries. A dog with a merle gene will be a merle. A sable with a merle gene is referred to as a sable merle .