8 week old blue merle
The controversial blue merle color is a
stunning swirl of black and gray that literally sparkles in the
sunlight. This color is becoming more and more popular in the
Pomeranian breed. There are several rules that one must follow in the
quest to breed a dog of this color. Since it is a dominant color, it
is an easier color to work with and requires fewer dogs to be kept
than most exotic colors.
Defining the Color
Let us start by defining the color. The merle gene dilutes the base
coat of the dog in a random fashion with a few exceptions. It works
primarily on the black or brown hairs (i) to create patches, heavy
ticking or a swirling pattern. Because it is simply a dilution gene,
the real color of the dog is the base color. I will use the
definitions and terms used by breeds in which merle is common such as:
Collies & Shetland Sheepdogs (Sable Merles, Blue Merles),
Australian Shepherds ( Blue Merles, Red/ Liver Merles.)
Blue merle – This is the classic gray/black pattern. The blue merle
is actually a black or black and tan dog with the dilution gene acting
upon the black areas of the coat. Pigment will be black. One or both
eyes may be blue, have blue flecks or be brown.
|Blue merle newborn puppies. The
pattern is evident at birth.
Red, Liver or Chocolate merle – This
is a chocolate dog with the dilution pattern acting upon it. This dog
will have a chocolate nose and pigment and the pattern will be
chocolate and silvery chocolate. One or both eyes may be blue, have
blue flecks or be brown.
Sable Merle – this is a sable dog with the merling acting primarily
upon the black hairs in the coat (i). In a heavily sabled dog the
pattern may be very obvious, while in a lightly sabled dog, it may be
imperceptible. The merling pattern is clear at birth but can fade
within weeks. An experienced breeder can recognize the distinctive
champagne color of the coat of an adult sable merle dog. Pigment of
the dog will be black. One or both eyes may be blue, have blue flecks
or be brown.
|This is a sable merle puppy.
You can see the pattern in the black hairs at birth. When
this puppy's coat started to grow, the merling disappeared
and only his blue flecked eye gave away his merle heritage.
Variations – Merle can dilute black
and chocolate each time it occurs including: black, black and tan,
chocolate and tan, dilute black (blue), blue and tan and dilute
chocolate (fawn/beaver/Isabella), sables, brindles. Merling can occur
in the color areas of parti-colored dogs. Other colors (red, orange,
cream) show little visual effect. One or both eyes may be blue, have
blue flecks or be brown.
Developing a Strong Program
In order to develop a strong blue merle program you will need to start
with an exceptional black program. Currently, the merles, like most
exotic colors are lacking in type. A good black and tan program will
also produce good blue merles. If your interest is in the red or
chocolate merle, you must start with exceptional chocolate dogs. Using
sables or oranges MAY produce blue merles, however it is less likely
than using blacks, black and tans or chocolates.
The merle gene is a dominant gene. This
means that it only takes one merle dog to produce merle puppies.
Statistically 50% of offspring will be merle. Improve your chances for
the color by using blacks, B&T and chocolates.
Currently, most merle Pomeranians have a somewhat rusty coat color
that needs to be improved. The optimal color is a medium, clear blue
with a black background. The rusty color we are currently seeing may
be due to the basecoat being a red/black. The best way to quickly
“clean-up” the color is to use a blue/black dog. Select for clean
colors, but select for conformation, soundness and type first. You can
improve the shade of the color in one generation.
The other theory is that the rusty color is the top end of the
hierarchy of merle coloration (iii). Again, select for the cleaner
colors, but conformation, soundness and type come first.
Things to Avoid
Avoid breeding merles to whites and creams. Many breeders think they
can clean the color or lighten the color by breeding to a white or a
cream, but this is not so. It is an entirely different gene. Also,
more importantly, if there are offspring born who do not have black on
them, it is difficult, if not impossible to tell if they are a merle
or not, unless they have a blue eye. At this point, without DNA
testing, we have no way to know, so they should be neutered and placed
in pet homes.
||These two puppies were born
without any black pigment. Until there is a DNA test for the
presence of the merle gene, puppies born this color should
be spayed or neutered and placed.
Avoid breeding brindles and merles.
Mixing a brindle in will make it difficult to distinguish the merles
from brindles at birth. Since the merle pattern is random, it can
appear as stripes in areas. Additionally, since the current blue merle
color is slightly rusty, it can appear to the casual observer to be
Most importantly, avoid breeding two merles together. If you avoid
doing this, you will avoid all of the controversial potential health
issues. If two merles are bred together there is a chance of producing
deafness and eye problems. While some breeds have almost an entirely
merle gene pool (the Catahoula Leopard Dog), we do not, so we have
other breeding options. A double merle in parti-colored dogs can
present a problem because it increases the amount of white on the
offspring. The white spotting pattern has been linked to deafness (ii),
so excess white is not desired. Prominent geneticists recommend that
dogs with more white than an Irish pattern NOT be used in a merle
A phantom or cryptic merle is a dog that appears to be one color but
reproduces like a merle. Any time there is the smallest spot of
merling on a dog, that dog IS a merle and will reproduce like one.
Offspring from each merle breeding need to be checked carefully at
birth to distinguish merles from non-merles. On dogs with a basecoat
of white or cream, the merling pattern shows little visual effect, if
any. Remember, merle acts primarily on black hairs or chocolate hairs.
IF there are no black or chocolate hairs to act on, it is very
difficult to distinguish the merle. Again, these dogs should be spayed
or neutered and removed from breeding programs.
Merle Patterns & Colors
The merle pattern is a random pattern, with no two dogs having the
same pattern. Each is as individual as a snowflake, however there are
some rules of color and pattern dominance. (iii)
The merle color comes in a hierarchy of patterns and colors. I will
briefly cover color here. For more detail, see the article Theories of
Coat and Pattern Dominance in Shelties - Notes on Blue Merle, Dilute
and White Factor by Cheryl Anderson.
|Both of these shades are
examples of blue merle poms.
The blue merle color comes in many
shades of gray from deep, almost black to a pale almost white color.
Currently we are seeing the colors at the upper end of the color
hierarchy in merle Pomeranians. Most are deep gray or a rusty gray.
According to the Anderson article, the order of dominance in color is
(from most dominant to less dominant) Pigeon Blue: a deep color
comparable to a steel wool pad, Pewter blue: a deep blue that can have
a brownish cast, Powder Blue: a glacial blue, Silver: a light clear
version without a blue cast , Dilute: the gray is dilute to an almost
white color. In breeds where merle is very popular, the powder blue
and silver are considered the most desirable shades.
There is current research being done to locate merle in DNA. (iv) Once
it is located, a test can be developed to determine merle from
non-merle dogs. This test will be invaluable since once it is
developed, there will be no more cryptic or phantom merles. Any dog in
question can be checked and declared either merle or not. Once testing
is done, dogs in question can be used with confidence in a breeding
The merle gene, although controversial, is here to stay. In breeds
where it is common, it has become a very popular color. Any color
breeding is challenging and this color is no exception. With a solid
foundation of quality dogs, a discerning eye and the conviction to
neuter dogs whose color is in question, it will not be long before one
will walk into the show ring.
(i) Sue Bowling;
(ii) The Veterinary Journal, May, 2003 – George M Strain, Deafness
Prevalence and Pigmentation and Gender Associations in Dog Breeds at
(iii) Theories of Coat and Pattern Dominance in Shelties - Notes on
Blue Merle, Dilute and White Factor - Cheryl Anderson
(iv) Schmutz, S. M., T. G. Berryere, and C. A. Sharp. KITLG mapping to
CFA15 and exclusion as a candidate gene for merle. Accepted by Animal
Genetics, July 7, 2002.