Probable/Possible Genetics Of Coat Colors In Pyrs

Catherine de la Cruz

Alleles according to Little 1

As
aw
ay
at

self-colored dark
Agouti (blaireau)
Clean tan - yellow-red

tan points

B
b
Black
brown (including red-tan-yellow)
C
cch

ce
ca
Full depth of pigmentation
Greatly reduced red-yellow pigment

Extreme dilution
Albinism
D
d
Dense pigment
Blue dilution
Em
E
ebr
e
Black Mask
Even distribution of dark pigment
Brindle
No dark pigment; even red or tan color

G
g
M
m

Grey paling
no paling
Merle
non-Merle
S
si
sp
sw
Solid color
Irish Spotting
Piebald
Extreme white spotting
   

Given the above, I believe that Pyrs can possess the ones in red italics.


A series – we see spots of both blaireau and all shades of tan from lemon to red

B series – we never see solid black

C series – although we see reduced pigment, we don’t see the “lilac” or “Isabella” colors produced by the ce and have never, to my knowledge, seen albinism.

D series – usually D, but I believe the d to be responsible for the “blue dilute” or “mealy” pigment seen in some dogs. I have identified “blue” nose, eye and lip pigment in pups and believe I can identify it in adults as well. These are often white dogs with light pigment.

E series –This gene is believed to influence the red in Irish Setters and Pomeranians. The e and a y alleles are most likely candidates for producing the yellow-tan-red series of markings in Pyrs.

G and M series – probably not an issue in the breed

S series – the s w allele comes with modifiers that allows for the expression (or not) of markings. In crosses I personally have seen between Pyrs and self-colored dark dogs, the pups include Irish and piebald markings, but never all white.

The alleles that are probably involved in the color of marking on Great Pyrenees are a w (agouti), a y (yellow-tan), E or e (red-yellow) and cch (chinchilla). If a Pyr comes from gray-marked aw (blaireau) parents, it is likely to have blaireau spots. A pup from tan-to-red ay or ee parents is likely to have tan-to-red markings. Pups from one blaireau and one tan-to-red marked parent may show either marking with, occasionally, the red having banded hairs, giving a red-blaireau – a wee - color

Little writes 2 “Just as tan-red animals produced by the combination of aya y ... can vary greatly in depth of color, so red-yellow individuals that are ee in formula show all grades of pigmentation from deep mahogany to very light cream, which may at birth appear white. It seems probably that the very dark and medium reds are those which have C, the gene for “full” pigmentation……In the other direction, it is likely that pale-yellow or cream coat color is produced by the interaction of the cch or ce genes with the ee combination.”

The latter combination may be the one responsible for producing “white” Anatolian Shepherds from fawn parents (and fawns from “white”.) It may also be responsible for the reported incidence of Pyr pups born apparently all-white, only to develop faint tan ears at a later date.

Later, in the same chapter 3 , Little writes, “There is considerable evidence that these two types of red-yellow coat colors (a y and e) can coexist in certain breeds. There is no way to check the proportions in which they occur, but the qualitative evidence for their coexistence may be sought for, recognized and presented.”

So what does this mean for the “orange” color in Pyrs? If the opposition to this color is due to the fear that a Saint Bernard may be in the background, the absence of the epistatic Em for black mask should prove the unlikely possibility of this cross. Given the natural occurrence of both types of tan marking (ay a y and ee) it is probable that all tones of the yellow-tan-red spectrum will be seen in the breed. One has only to see the range of colors, from crème to red, present in Golden Retrievers, which are self-colored ee . If one were to examine the Standards for all dogs that have non-black color, it will be seen that it is described by different names – “fawn” Dane, “gold” Golden Retriever, “red” Cocker, “lemon” English Setter - even “dried grass” for Chessies. So what is “red-tan” to one observer might be “orange” to another, or even “rust”.

Some breeds, like Bernese Mountain Dogs, have suffered greatly by being selected solely for color and markings. When this is done, more important genetic qualities such as temperament, health and soundness, are often overlooked. If “orange” is simply a natural expression of one of the yellow-tan-red genes, then it should not be discriminated against. If individual breeders want to breed only blaireau, or only tan and red, that should be their choice. But to have a group of dogs excluded from the ring, or barred from receiving their championships, simply due to the shade of an acceptable color, is a step in the wrong direction in our quest to breed healthier, sounder Great Pyrenees.


1 The Inheritance of Coat Color in Dogs; Clarence Little, ScD Howell Book House, 1959
2 ibid – page 53
3 ibid – page 60

Note: This is from a letter written to a British Pyr breeder at the time the Pyrenean Mountain Dog Club was considering making "orange" markings in Pyrs a disqualification, despite it appearing as an acceptable color in the FCI standard.