THE A B C'S OF COLLIE COAT COLOR INHERITANCE
The five basic coat colors in collies (in Canada) are sable, tricolor, blue merle, sable merle and white. With certain crossings of the merle factor another color can be produced....white merle.
For simplification, the following letters represent colors:
S = SABLE, dominant over tricolor. Shading may run from straw through red to dark mahogany.
PS = Pure For Sable. Usually a clear shade of straw or orange red without dark masking or fringes. These individuals carry no tricolor gene and can produce only sable color regardless of what color is combined with them.
Tri = TRICOLOR. Recessive to sable, Black collies with white and tan markings on sides of muzzle, above eyes, sides of cheeks, chest and inner margins of legs.
tS = Tri Factored Sable . Sable collies carrying the tricolor gene in conjunction with the dominant sable gene. Usually (but not always) a dark orange to a very dark mahogany in color with dark masking and fringes.
BM = Blue Merle . Bluish gray with black splotching, carrying sable markings in the same pattern as the tricolor. Color results from the interaction of the dominant dilution gene (M) with the tricolor gene (t).
tSM = Tri Factored Sable Merle. Usually a darker sable color than the PSM with dark brown merling which quite frequently is still visible at maturity. The tricolor gene is present in conjunction with the sable and merle gene.
PSM = Pure For Sable Merle . Usually a light or even "washed out" sable at birth with brown merling. At maturity, quite often these collies lose their merling and coat color becomes a clearer red. No tricolor gene is present in their makeup.
WM = White Merle . Resulting from the combination of two merled parents. These collies inherit the dominant dilution gene (M) from both parents. Thus, color is diminished almost to the vanishing point by the gene in duplex. They are almost white in appearance and may or may not have a few merling spots. Breeding a WM to a Tricolor will result in an entire litter of blue merles. This is not true of white merles carrying the PS genes or the tS genes when bred to a tri.
White = White CHW. These collies are the result of a cross between either two white parents or white factored parents. Color is carried on a recessive gene (w) and is inherited INDEPENDENTLY of sable, tri , blue merle or sable merle and may occur in combination with ANY of them.; A blue headed white is just as sound and normal as a collie as the tri or sable headed white. These are not to be confused the the white merle whose "white" color results from the double dominant dilution merle gene, whereas the white color of a blue headed white results from the recessive gene (ww) and its blue color from the normal interaction of the merle gene with tricolor.
wf= White Factored . Colored dogs usually with large white frill, heavy white tail tip, possibly a body splash of white hairs and white extending upward from the hind feet over stifle to meet the white underbody.
Non wf = Not White Factored. Regular colored collies NOT carrying the recessive white factor.