The Shetland Sheepdog comes in several colors with varying amounts of
white and/or tan.
SABLE - Sable is probably what most people think about when they think of Shelties. Sable ranges in hue from light
golden sable to a deep mahogany (that can be almost black it is such a dark brown) with various shades in
between. Sable is the dominant color.
TRI COLOR - A tri color Sheltie is a black dog with varying amounts of white and tan.
BLUE MERLE - The Blue Merle is a dilution of the Tri Color. The black is diluted out to grey with varying amounts of
black mottling or merling. The grey can range in shade from an icy gray to dark grey. The Blue Merle has varying
amounts of white and tan.
BI BLACK - This is basically a black and white Sheltie
BI BLUE - This is a Blue Merle and White dog without any tan points (what you get if a Bi Black has the dilution gene).
SABLE MERLE - This is a Sable dog with a dilution gene. Sometimes it can be difficult to tell a Sable from a Sable
Merle. (see photos at bottom of page)
COLOR HEADED WHITE - This is a dog with a primarily white body with some colored spots and color on the head.
This happens when the white factoring (what helps determine the amount of white on the dogs) gets a little "out of
control." CHWs (color headed white) are not AKC showable in Conformation but they are in UKC.
DOUBLE MERLE (. Double Dilute White) - This is what happens when two merles (either blue or sable) are bred
together. The doubling of the dilution gene causes almost totally white dogs. Double Merles are also prone to
hearing and vision problems so breeding two merles should be avoided. However, Double Merles can be very
valuable in a breeding program. Breeding a Double Merle to a tri or bi black will almost always produce 100% blue
Elementary merle genetics for newcomers
This is and is intended to be a very basic explanation of the workings of the merle gene. If you already know about
double merles and sable merles and such, you may not find anything new here, but you're welcome to stick around
and comment. If you're not sure why people get upset about sable merles and double merles, stick around and
There is no such thing as a sable merle gene or blue merle gene. There is only a merle gene. Merle is a dilution
gene, that is, it lightens whatever the coat color would otherwise have been. The lightening is not spread evenly
over the coat, but leaves patches of undiluted color scattered over the dog's body. Also, the lightening seems to
work primarily on the black pigment in the coat, so any tan on the face stays even. Note that "black" as used here
includes liver or chocolate. These colors are rare color faults in Shelties, but everything written here applies also
to other breeds with the merle gene, including Australian Shepherds. A red merle in that breed is produced by the
merle gene acting on a liver (solid red-brown, not the same as sable) coat.
One dose of the merle gene on an otherwise black dog produces a blue merle - a more or less bluish gray dog
dappled with black spots. Tan points - the tan spots over the eyes, on the sides of the muzzle, on the legs and
under the tail of a tricolor dog - will still be there in the merled tricolor. If the tan spots would not be present in a
black dog, giving what is usually called a bi-black in Shelties, tan will not be present in the merled black either, and
the dog will blue merle and white without tan: a bi-blue. One dose of the merle gene on an otherwise sable dog
produces a sable merle. Sable merles are less predictable in color than blue merles, and may range anywhere from
an apparent sable, often with a pinkish or orange cast to its coat, to something that looks like a very rusty blue
merle. White markings remain on the merled dog, and may even be slightly more prominent.
Merle acts on the black pigment in the iris of the eye just as it does on the coat, so merle dogs often have part or
all of the eye blue. (This does not affect their vision, though since it happens to some extent in the retina as well it
may make it harder to diagnose certain eye problems.) The Sheltie breed standard allows blue or merle eyes in blue
merles, but not in sables. Thus a sable merle with blue or merle eyes will not do well in the show ring.
Notice that I said a single dose of the merle gene. There are always two copies of a gene, alike or different, in any
dog. If we call the merle gene M and the non-merle gene m, any given dog can be mm, Mm or MM. The mm dog is
the normal, full-colored tri, bi-black, or sable in Shelties, or liver (red) in Australian Shepherds. The Mm Sheltie is a
blue merle or sable merle, depending on what color it would have been without the merling gene. An MM dog,
often called a double merle or a homozygous merle, will be mostly white and usually deaf or blind and often with
other physical problems. Some MM puppies are born completely without eyes.
On average over a large number of litters, breeding merle to merle will produce one fourth full colored dogs, one
half merles and one fourth defective whites. Breeding merle to full color will produce one half full color and one
half merles, but no defective whites. The merle to full color breeding, then, produces just as many merles as does
the merle to merle breeding, and without the danger of defective puppies. The safe breeding for a merle, then, is
to a non-merle mate. This breeding should produce all healthy puppies, and about half will be merles.
To breed in this way, it is important to know which dogs are merles. This is one of the reasons experienced
breeders rarely breed blue merles to sables, as this mating may produce sable merles.
Sable merles are no more likely to have health problems than any other color, and they are equally good
companions. Many do have colors that are not accepted in the show ring, either because they have blue or merle
eyes or because the mottling produced by the merle gene is too obvious. The real argument against sable merles
is that they may be mistaken for normal sables. If two such sable merles were mated together, the resulting litter
could contain defective whites. What a shock for the breeder expecting normal, healthy puppies!
There is one kind of breeding that can produce all or almost all merles, and that is the breeding of a tricolor or a
bi-black to a double merle - but remember that the double merle has a high probability of being blind or deaf. A very
few breeders have been lucky enough to get high quality homozygous merles that are not too severely affected to
breed - but it definitely takes a lot of luck and really top quality blue merles to start with. Merle to merle breeding
are only for the very experienced breeder who knows her lines and what they will produce - and it has probably
produced more heartbreaks than good homozygous merles, even for them. A blue merle from black to homozygous
merle breeding is just as healthy as one from a more normal black to blue merle breeding. There are now three
homozygous merles on the Register of Merit list: Merri Lon the Blue Tail Fly ROM, Shamont Ghost of a Chance ROM
and Shadow Hill's Double Trouble ROM. Note that not one of these dogs is a Champion - double merles cannot be
shown. Not only are Shelties more than 50% white severely penalized in the breed ring, most double merles have
severely defective hearing, and a deaf dog cannot be shown at all.
Unless you have done a lot of merle breeding and really know what you are getting into, the safe rule is still that a
blue merle should be bred only to a black (tri or bi).
Note that in Shelties, all blue merles imported to this country can be traced in direct merle-to-merle line to crosses
involving blue merle Collies.
Sable Merle photographs
The sable merle color is subject to a great deal of controversy. On the one hand, it is a predictable color in the
breed, given that both blue merle and sable are acceptable colors in the breed, and it is a natural result of crossing
these two colors. On the other hand, it is not addressed at all in the breed Standard, which lists only sable
(including sable and white), black with tan and/or white, and blue merle with tan and/or white.
This failure of the breed standard to address sable merle can be considered the root of the problem. On the one
hand, It has been traditional in Shelties not to breed sable to blue, and not to show any sable merle offspring if
such a mating is made. People who feel this way generally argue that the Standard does not address sable merle
because those who wrote the Standard never considered the possibility that they would be deliberately bred, let
alone shown. At the other extreme, both merle and sable genes exist in the breed, so they will occasionally come
together in the same animal. Some people argue that the Standard does not say that a sable has to be all the same
shade of sable, and even argue for accepting blue eyes (a normal effect of the merle gene) in sable merles.
There is occasional talk about changing the Standard to address the problem of sable merles. However, the two
extremes are not at all in agreement as to what changes should be made. The "conservatives" would probably opt
for making sable merle a faulty color, possibly by severely penalizing blotchy shading on a sable or by explicitly
recognizing sable merle as a fault. The "liberals" would probably want sable merle recognized as a fourth color
division, with blue eyes acceptable in sable merles. Obviously both sides could not be accommodated in a Standard
revision, so the Standard remains unclear.
My own concern is primarily with the identification of sable merles. While sable merles are normally recognizable as
puppies by the appearance of a merling pattern, this is not necessarily true in adults, especially pure for sable
merles (two genes for sable and one for merle). A/C Ch Laureate Santana is a pure for sable merle, though in his
case the merling can be seen on the tips of his ears. If such a dog is registered as a sable, which might be done
through ignorance or in order to be sure it could be shown as a sable, there is a real possibility that a person
unaware of merle genetics could mate two sable merles thinking that both parents were ordinary sables, and get a
litter with one or more defective whites - a normal occurrence when two merles are mated (which is why the
recommended mate for a blue merle is a tri or bi) but not expected in a sable to sable mating.
SABLE TRI -Blk/Wht/Tan BI BLACK-blk/wht
SABLE MERLE COLOR HEADED WHITE
SHELTIES COME IN MANY DIFFERENT COLORS.
BLUE MERLE (with Tan ) BI BLUE (no tan) DOUBLE MERLE