The article below appeared on Sat., Nov. 7, 2009 on

CONTENTS |                  


 It Is What It Is! Thoughts on Joan Graber’s:
“A merle is a merle is a merle! Isn’t it?
By Kathy Moll, Deep River Collies

“A rose is a rose is a rose.” (Gertrude Stein)

In the study of logic, the Law of Identity simply says that a thing is the same as itself. In our modern lexicon, “It is what it is!”

The highly regarded Collie breeder and judge, the late Joan Graber, cleverly applies the Law of Identity to the merle gene in Collies in her October 1991, article on the sable merle and Standard revision published in the CCA Bulletin. Joan was one of many Collie breeder/judges of the past who believed in the truth of two basic issues that came to the forefront 18 years ago and again today.

The two issues are paradoxical. Issue # 1 is that sable merles are as normal, healthy, and similar in quality to comparable Collies of other colors. Issue # 2 is that sable merles should be specifically included in the Collie Standard.

To illustrate that sable merles have been an important part of Collie breed development, Joan discusses the history of the merle beginning with 19th century Collie breeders in Great Britain. She bases her conclusions upon what the early creators of the modern Collie wrote and what they did based on very old pedigrees and color/ pattern descriptions that they included.

From the historical evidence, she draws some conclusions. As the earliest Collie Standards assert, color really was “immaterial” to these Collie breed developers, and they seemed to view sable merles as neither positive nor negative but simply as a fact illustrating “it is what it is.” A lack of genetic information meant that early breeders simply used the best available individuals, including “dappled sables,” in their breeding endeavors and may not have made a connection between merling as a pattern and sable coat color.

For example, the great grand dam of CH Metchley Wonder, a bitch named Bonnie Greta, is described as “dappled sable” as is Duncan, Wonder’s great-great grandsire. Since Wonder was whelped in 1886 and his son, CH Christopher, in 1887, the above mentioned sable merles were born circa 1880. CH Christopher is behind all modern Collies and, therefore, so are his sable merle ancestors.

Since merles were the most commonly seen herding dogs of the 19th century, the gene has been around for at least 150 years. Dr. Leigh Anne Clark and her team, who mapped and sequenced the merle gene in 2005, tell us that it is the same gene in all breeds. She and her fellow genetic researchers draw the conclusion that “the breeds analyzed in this study (the mapping /sequencing study) share a common ancestor,” and that “the occurrence of merle in many breeds and the fact that the first breeds to diverge from the working sheepdog population in the 1800s have merle patterning . . . suggest that the founding mutation may predate the divergence of breeds.” So, the merle gene is older than the Collie breed itself.

Joan points out that the very commonness of the merle gene may have been the reason it was “out of favor” in early Scots, Irish and English Collie show dogs. We should feel fortunate that the beauty of the merle was saved from possible oblivion by early American Collie breeders who saw the unique possibilities in the pattern.

“If you would understand anything, observe its beginning and its development.” (Aristotle)

Moving forward in the early 20th century, Chris Casselman and Thomas Halpin built the famous Hertzville Collie line based on Lodestone and Tokalon stock. Trudy Mangels explains in her Evolution of the Collie that by the 1930’s, Hertzville Collies were best known for excellent head qualities, but had also developed Collies who won Best in Show awards (6 in 1939 alone). CH Hertzville Headstone and his two sons CH Hertzville Historian and CH Hertzville Headstudy were among their best known BIS winners. Headstone was a major winner in the ring and an excellent producer. He was a sable merle. He produced 10 champions and would no doubt have had many more had he not died prematurely at age 6 years. He influenced many Collie lines and was the double great grandsire of CH Hazeljane’s Bright Future, the 4-time CCA National Specialty BOB winner.

Joan quotes such past authorities as Thompson Gray, Dr. O.P. Bennett, Charles Little, Trudy Mangels, Dot Gerth, and Bobbee Roos and mentions several Collie breeders of the late19th and early 20th centuries. Their thoughts and information are illuminating and instructive. Joan repeatedly calls upon Collie fanciers to “go study your genetics.” She explains that prejudice against the sable merle and fear of including the pattern in the Standard has often been based upon lack of genetic understanding. She likens these prejudices to those disallowing blue marked white Collies until the 1977 Standard revision because some breeders confused them with double merles. Likewise, she compares the prejudice to past hesitation to do rough to smooth breedings to improve Collie quality for fear of producing a coat hybrid.

All three prejudices are based on erroneous beliefs about genetics. Study genetics, study breed type, study Collie history. These are points that Joan makes throughout her article. Education is an ongoing process for all Collie fanciers regardless of longevity in the breed and regardless of experience!

Much has been made of “educating CCA members” about the sable merle this time around as well, and so it should. However, there appears to be disagreement about who has been sufficiently educated and what they know and do not know; what they understand and do not understand. To deny the general membership the right to a viewpoint on the grounds that they are uneducated and inexperienced flies in the face of logic and is insulting. Who has made that decision and upon what evidence is their opinion based? Attempts by some to portray CCA members who support the sable merle as uneducated beginners are gross mischaracterizations! Most proponents of the sable merle and revision are well educated, well informed and well intentioned as are most of their opponent counterparts. Make no assumptions without clear evidence!

My own observations of sable merle and Standard revision discussions over the years tells me that something of a consensus has at last been reached by most 21st century breeder/exhibitors and all but a few Collie specialist judges. With a few notable exceptions, most fanciers appear to agree (at least in theory) on Issue #1 — Sable merles are as normal, healthy and as similar in quality as comparable Collies of other colors. In fact, some who oppose Standard revision use this issue to “prove” that sable merles are covered in our current Collie Standard.

Thus, we come to Issue #2 – Sable merles should be specifically included in the Collie Standard. This, of course, involves revision to the Standard. Here fanciers definitely part company and generally fall into two camps: “They are covered as is”; or, “They are not covered as is.”

The Collie Standard must strive for clarity, must reflect scientific/genetic information as it becomes available, must provide vital information for breeders and judges toward the “ideal” in virtues, and must include guidelines for assessing faults and their degrees. Failure to apply these precepts to our Standard is a serious breech and a disservice to the Collie breed. These are the very reasons that periodic, thoughtful revision is needed to make our Standard the best it can be.

Some opponents say a sable merle revision would be a hasty move! It’s been 18 years since the last thorough discussion and poll of the members. At that time, revision was favored by a majority of the members, yet a few made the decision for the many, and no revision occurred. Sable merles have been contributors to the Collie gene pool for at least 130 years. Discussions of Standard revision to include them happen every 15 to 20 years with a majority in favor, yet no action is taken. Hasty? I think not! As Joan’s article did 18 years ago, this article also covers most of the objections to Standard revision and presents counter arguments.

Revisions should be made to clarify. If our standard was clear about the sable merle, we would not be having our current discussion. The very fact that we’re arguing proves that the Collie Standard lacks clarity on this point. Judges as of a few weekends ago continue to withhold ribbons for lack of merit because of blue in eyes. In conversations with other breeder/exhibitors, I made some discoveries. One bitch that needs a major to finish and has won under specialty judges, had ribbons withheld by a judge at a specialty because she hone blue eye. The same judge has given a specialty BOV at a very large entry to a different sable merle that also has one blue eye.

Other recent comments at shows include a judge who pulled 2 bitches for winners, and then suddenly exclaimed, “Oh, I didn’t notice that.” The “that” was some merling on one ear. The other bitch won immediately thereafter and the sable merle was not even considered for reserve. Another judge opponent of revision has given a sable merle with one blue eye and one brown Group placements at large entry shows while writing that sable merles are unacceptable in the show ring.

A well known opponent of standard revision, especially of blue in eyes, recently spoke to an exhibitor at a specialty whose sable merle had just finished. The opponent to revision complimented the exhibitor upon how beautiful the bitch was and how she deserved a specials career because of her quality. When the exhibitor expressed hesitancy because her bitch has one dark brown eye and one dark blue one, the revision opponent explained that the blue eye was not important!

More than one breeder judge has told me in personal conversation that to put up a quality sable merle with blue in its eyes means that he/she “just ignores” the part of the Standard that disallows that. Should judges have to “ignore” part of the Standard to reward the Collie that comes closest to it in his/her opinion?

Recently, a sheltie/breeder judge who had a Collie assignment explained to a couple of Collie exhibitors that a simple Standard revision to clear up the sable merle conundrum would be appreciated.

The Collie Standard says, “In blue merles, dark brown eyes are preferable, but either or both eyes may be merle or china in color without specific penalty . . . Except for blue merles they are required to be matched in color.” A simple examination of the word “required” (an absolute) illustrates that sable merles with even a small blue fleck in one eye do not have the “required” match. Therefore, judges are compelled to ignore that requisite in order to reward such a Collie for outstanding virtues. If Collie aficionados are this conflicted, imagine the confusion for all-breed judges! I truly believe that clarity IS needed. Contradictions and inconsistencies about the standard as it applies to sable merles are still common place, and the practical application of the Standard is, even now many months “post directive,” all over the place.

Joan uses the arguments presented by opponents of revision to include the sable merle and counters them. For example, one argument goes like this: “If the old breeders didn’t think sable merles should be included, who are we to do so?” Joan asserts that the “old breeders” that opponents are speaking of “are ’old’ only in that they preceded us, but they were not older than those breeders of the 1800’s to whom color really was immaterial.” The oldest breeders/developers of the Collie breed believed that color was immaterial and wrote the Standard so that it included that wording. Later revisions to the Standard changed that wording. How old is old? Is 150 years too old? How about 75 years, or 50? Would 30 to 40 years qualify one as an “old” breeder? What is too old; what is too new? “With age comes wisdom.” Well, maybe in some cases, but let’s face reality: “Age doesn’t always bring wisdom; sometimes age comes alone.” Logic dictates that wisdom and knowledge in some areas does not equal wisdom and knowledge in all areas.

However defined, there is disagreement among “old” breeders concerning sable merles and Standard revision and there always has been. So to which breeders of the past do we defer? Are current CCA mentors “old” enough? Is every “old” breeder a CCA mentor? Should fewer than half of the total mentors influence the revision decision for every CCA member? Should a 6-person review committee, all of whose members, save one, oppose revision, make the decision? Should the club president decide for 2000+ members? Furthermore, a purported AKC mandate concerning revision is mysterious indeed. AKC makes no decision for parent clubs to whom breed standards belong except in the final phase. During this last phase, exact revision wording that has been voted upon by the full membership and approved by a 2/3 majority is presented to AKC for approval. Even then, AKC is deciding to approve or disapprove wording based upon whether or not it conflicts with AKC rules. CCA owns the Collie Standard and, like other parent clubs, agrees to allow the AKC to use it.

The standard should undergo revision when genetic information and science dictate. Joan uses the blue marked white as an example. In addition to this 1977 revision, changes based on new scientific knowledge were made to the description of Collie gait. In the 1950 reworking, four colors were added to the Standard, including the blue merle. Prior to that revision, many other changes were made to reflect increasing knowledge. Why is this case different? It isn’t!

Articles published in scientific journals in recent years have added new information to our understanding of the merle gene. Why would we close our eyes to this new educational opportunity? Why not apply what we know now? Our Standard attempts to describe the ideal. This does not mean that the attempt at such description in itself equals perfection. The Collie Standard is better than most breed standards and is a tribute to the work of many individual fanciers over the past 100+ years. It has undergone quite a few rewrites and revisions throughout Collie history. Its authors have said nothing, to my knowledge, to indicate that they believed their writing was “perfect.” We are striving for perfection in our breeding programs in actual living, breathing Collies. There is no evidence that breeder’s of the past wanted future breeders to treat the Collie Standard as though it were “written in stone” when clarity and science dictate otherwise. While describing desired virtues, the document also assesses faults and the degree to which they should be penalized.

“We can’t encourage blue eyes in sables,” is the most vehement argument against sable merle inclusion, and Joan addresses it. She does so with the genetic information available to fanciers in 1991. Most of that information is on the money. However, we know even more in 2009 about the merle gene than we did in 1991. For instance, we now know that the merle gene is an insertion gene that randomly copies itself and that the length of its “A” tail is also random and accounts for wide variation in merle patterning. We also know that this same randomness applies to eye color in all merles. Those with the insertion gene present as merles, but the gene’s “A” tail length controls the degree of merling as well as the randomness of eye color. Both blue merles (homozygous, for black and tan) and sable merles (homozygous for sable, as well as heterozygous for sable) have random chances for pigmentation in the eyes.

The same mutation insertion and incomplete dominant mechanisms that randomly put merling on these Collies also produce the following possibilities on eye color: both eyes brown; both eyes blue; one eye of each color; partial blue and brown in one or both eyes; and blue flecks in brown eyes. So while eye size, shape and set are genetically controllable through selective breeding, the presence of blue or merling in the eyes of merles is not. Breeders do not have the option to “breed for blue eyes,” even if they ignore the Standard’s preference for dark brown! A sable merle with two blue eyes is no more likely to reproduce them than is a sable merle with two brown ones, according to the best available genetic studies. Either will produce randomly occurring brown, blue and merling in eyes in offspring just as blue merles do. If such were not the case, we would have seen an ongoing increase in blue eyes in blue merles. No such thing has happened! “A merle is a merle….” and “it is what it is.”

While dark brown eyes would be the preference of breeders and fanciers in both blue and sable merles, blue in eyes may or may not detract appreciably from the merle’s expression and is an individual matter of proper evaluation. The Collie Club of America Standard Review Committee’s own report uses quotations from breeder/judges concerning specific sable merles shown to them. One of the common themes that emerges is beautiful expression. Many of the sable merles to whom they attribute sweet expression have blue or merling in eyes and even total blue. All well educated Collie folk know that color is only one of many contributors to expression. Joan says, “Not only the color but also the size, shape, placement, large or small haw, light or dark haw, affect expression. In all cases we are dealing with our definition of expression, and we need to remember expression is an aesthetic rather than a functional attribute.” She goes on to quote Bobbee Roos on the subject of coat color: “True Collie expression is inevitable regardless of color because of the head properties.”

Blue merles were included in the 1950 rewrite of the Standard. Over the past 59 years, their inclusion with merle or blue eyes allowed, but dark brown preferred has contributed to the breed, not harmed it. Merles exist, fanciers use them in breeding programs, many exhibitors show them, none of that will change. As for judges, a West Coast friend recently made this point, “If the judge feels that the blue eyes affect the expression of the dog, the judge will place the dog accordingly. The exhibitor will face the same considerations in deciding whether or not to show the dog. I suspect that by changing the Standard, we won’t see either an increase in blue eyes or a significant change in the number of blue eyed sable merles put up.” I agree with my friend! “A merle is a merle…” Revision is made to clarify and to reflect new scientific knowledge!

Another argument, “We open up the Standard to other changes, some of which might be bizarre,” is specious. Only a few opponents of revision have brought it up to my knowledge. Proponents have stayed on point. This revision is ONLY about a long over due, decades-old request for revision to include the sable merle. That was all that the membership meeting vote addressed and is all that 71% of all CCA members cast their votes for or against.

Misunderstanding abounds about what is involved in revision. Our own constitution calls for a process; even though, in my opinion, it hasn’t been properly followed so far. With the assumption of power comes responsibility. For any elected official there is always a mandate to follow our constitution, be honest with the membership and make its wishes a prime consideration!

“So what’s the turmoil?” Joan asks. Those who have suggested possible revision language have done so in ways that are unobtrusive but clear. The sought after revision described by many proponents requires but a few words and affects less than 1% of the Standard’s language to clarify and reflect current knowledge!

Joan tells us, “Those who say we should not be accommodating the Standard to what we are breeding, or that our present Standard was outlined by our founding fathers, need to review all the Standard changes since the mid 1800’s . . . I would like to think that we make changes in the Standard to clarify certain areas for breeders and judges as well as to correct errors as we gain more knowledge, especially in areas of genetics and inheritance.” Since we’ve been breeding sable merles continually since the 19th century development of the breed, we’re hardly accommodating the Standard to a fad! As Joan also reminds us, “The sable merle is not going to go away.” And I would add, “Why would we want it to?”

Related article> A merle is a merle is a merle! Isn’t it? by Joan Graber, Rudh’Re Collies

 The article below appeared on Sat., May 16, 2009 on www.colliesonline

“The Coat of Many Colors”

“Life is a celebration of passionate colors.” (L. Cator)

Much is being discussed of late – actually for the past few decades – about sable merle collies, the breed standard, and color/pattern genetics. Thanks to the “leaps & bounds” growth of DNA research and the work of a few dedicated veterinary geneticists, we have far more solid science available than ever before to teach us about color and pattern in our wonderful breed. 

This article is about the dedicated work of Dr. Leigh Anne Clark and her colleagues at Texas A&M and that of Dr. Phil Sponenberg of Virginia Tech and his colleagues. Their studies and research with various dog breeds have brought color/pattern genetics into focus and answered important questions for breeders.

In 1984, Dr. Sponenberg published a study in The Journal of Heredity involving 66 puppies from a double merle Australian Shepherd from which he concluded that the merle gene was due to a mutation by what is called  “transposable DNA .”

In 2005 Dr. Clark and her colleagues successfully mapped the merle gene in all breeds, sequenced the merle gene of Shetland Sheepdogs, and published their findings in The Proceedings of the National Academy of Sciences, in January 2006, under the catchy title, Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog. Dr. Clark’s research was based on Dr. Sponenberg’s earlier work with Aussies. I am the conduit for their expertise and that of my good friend, molecular biologist Dr. Mike Vaughan. Mike is a fellow collie fancier and CCA member who helped me “translate” the science so that I could relay it accurately to you.

Collie Color:
The two base colors in collies are sable and black & tan. Most of us know, that in collies, sable is dominant and tri-color recessive. A puppy inherits one color allele from each parent.  An allele is an alternate form of a gene. Therefore, if a collie inherits a dominant sable allele from each parent, he/she is a “pure for sable”  (homozygous for sable). On the other hand, if a recessive black & tan color allele is contributed by each parent, the collie will be a tri-color (homozygous for black & tan). Some collies inherit a sable allele from one parent and a black & tan one from the other making them “tri-factored” sables (heterozygous genetically although still sable in appearance).  

 Dr. Mike explains the process:

Specialized skin cells in Collies produce pigments called melanins; these pigments come in black or tan. These are not free dyes, dissolved in the cell water but instead are solid pigment particles built up in tiny bodies made of proteins called melanosomes. The skin pigment cells pass these melanosomes into hair follicle cells which produce the hair strand.  If a hair follicle does not receive pigmented melanosomes, the hair strand it forms is white, as in the majority coat of a white Collie or the neck region of colored collies (from the Irish pattern gene).  If all the melanosomes that a growing hair strand receives contain black melanin, the hair strand itself will be black, as in the black areas of a tri-color Collie. And if the melanosomes the follicle receives from the pigment cells are all tan, the hair strand will be sable, as in the coat of a pure sable or tan points on a tri-color.

All cells of a Collie have the same basic genes, but no single cell expresses all those genes; instead, in each cell, some genes control the expression of others, turning some on and some off.  This complex and miraculous control process not only produces beautiful puppies; it continues throughout the life of the dog. 

An example is the mahogany sable coat of tri-factored sables. At birth these puppies are usually dark tan. But as older puppies, many look much like pure sables, and almost all the developing hair in the first coat is sable. However, as the tri-factored collie ages, some black melanosomes are put into the growing hair strands, so the coat develops a deepening dark appearance. 

Sable Merle & Blue Merle Genetics – Separating Fact from Fiction:  

Dr. Mike tells us, “The merle allele is not a color allele; in fact, it produces no pigment at all.” A misconception that is apparently still alive and well is that sable merles are a mysterious mishmash of colors in conflict.  This is fiction. A sable merle is not a combination of sable, tri and blue.  Here’s why. There is no color gene in collies for blue coat color, only sable and black.     

The merle allele “dilutes” color on the body. In genetically black dogs, it turns the black coat grey but allows some melanosomes to be fully loaded with black pigment so that black color comes through completely on some parts of the coat. The merle gene has the same affect on a genetically sable collie, turning most such collies a lighter sable. 

Of course, when a collie has one sable color allele and one black & tan color allele, it is still a sable, just a darker one. This phenomenon is called incomplete dominance (an interaction between alleles/genes). Incomplete dominance means that the black and tan recessive allele in a tri-factored sable is only partially suppressed by the dominant sable color allele. The sable phenotype (appearance) is expressed, so it is dominant (or, more accurately, incompletely dominant) while the suppressed black & tan allele is incompletely recessive because it does darken the sable by adding in more black. The resulting collie is, of course, still a sable. So when a merle allele with no pigment acts upon the coat, various shades of sable come through.

Sable merles, whether pure for sable or tri-factored sable, are still sable collies; one is simply a darker sable than the other.  There is no conflict among the genes; only a normal, expected and predictable interaction!

Collie Merle Pattern:
Again, keep in mind as you continue to read that the merle allele is NOT a color allele. I know we’ve said this before, but it’s worth repeating!

We’ll need a few definitions to understand how merle works. For example, we briefly mentioned the meaning of allele earlier. Here’s an expanded definition: An allele is one of two or more alternative forms of a gene at the same site on a chromosome that determine alternative characteristics in inheritance.

SILV, a term in the title of Dr. Clark’s paper excerpted later in this article, is a gene that is important in pigmentation because it produces a protein that forms the matrix (background) on which  melanin is deposited. When SILV is used to refer to a gene, it is italicized in scientific writing. When SILV refers to proteins in such writing it is not italicized. I have tried to adhere to that practice in this article.

 Transposable DNA, also called SINE or retrotransposon, is another term we need.  These three terms are interchangeable. These refer to sections of DNA able to copy themselves and inset themselves at random into other areas of DNA. All merles have a SINE  inserted in the SILV gene. A SINE is organized into 3 parts: a head, a body and a tail. The tail is a fragile string of “A” nucleotides. Nucleotides are chemical letters in the DNA code. The “A” tail may shorten or lengthen each time it is copied.   

The length of the “A” tail controls the degree of merling seen in a collie. A collie with little or no “A” will present as a cryptic. A cryptic is a merle who is not physically distinguishable as such or who mainly looks tri-color or sable with only small areas of merling. Collies with longer “A” tails in SINE present as merles, but the tail length controlsthe degree of merling and is responsible for the random degree of  mottling as well as the randomness of eye color.

Dr. Clark summarizes the merle allele’s affects this way:  Merle is a coat pattern caused by a dominant mutation in a pigmentation
gene called SILV. The mutation (an insertion of repetitive, mobile DNA) causes dilution of the base fur color and often blue eye color. Merle affects all coat colors, but is more apparent in dogs with darker-colored coats (e.g., black) than those with lighter-colored coats (e.g., sable). Coat color is determined by other genes. Because of the type of mutation that causes merle, merling is random and characteristics such as the size and number of colored patches and eye color cannot be predicted.

So how does the mobile, inserted “transposable DNA” (remember that synonyms are SINE & retrotransposon) in merle interfere with the production of SILV protein needed to form pigmented melanosomes? Dr. Mike explains with an analogy that the insertion works on pigment in the following way:  “It is as if a nonsense string of letters is inserted at random into a meaningful sentence, making it impossible for us to read it.”

A blue merle is a tri-color (homozygous black & tan) with the merle allele of the SILV gene. A sable merle is a sable that can be either homozygous sable or heterozygous sable with the addition of a non-color producing merle allele. Merle actually has the affect of preventing some of the color from fully appearing on the collie. 

Dr. Mike explains further:

With the addition of merle, things get interesting!  The “transposable DNA”  inserted into the merle gene contains a long string of “A’s” that “turn off” the SILV gene so that it cannot produce the SILV protein helping to form melanosomes. It turns out that mutations occur in this string of “A’s”quite often as cells divide, decreasing the string’s length. The result is that the body of a tri-color (with merle) develops, first as an embryo and later after birth, with clones of skin cells with new mutations in the “A” string. The shortened “A” prevents the “transposable DNA” from inactivating the SILV gene, allowing normal melanosomes to be made again. In other words, now there are two mutations present, with one reversing the other. So this clone of skin cells, with normal melanosomes loaded with black pigment, will produce a spot of hair that is black or dark grey.  This spot on the puppy now has two mutations, one reversing the other. Since there are a lot of these spots, some dark gray and some quite black, scattered randomly over the dog’s body, the puppy ends up with the classic “blue merle” appearance.

This is amazing!  When you next look at a blue merle Collie, look at the spots of black and grey on its body, giving it its beautiful coat and think that you are literally looking at mutations, creating each unique spot.  The SINE gene is still there in the SILV in those spots; it has just been inactivated in them, by the second mutation decreasing the length of the string of “A’s.” One mutation is canceling the effect of another. You always knew Collies were clever!

I should add that the merle mutation also often affects the eye color of dogs inheriting it; the effect is to produce one eye or both eyes that are completely or partially blue.  This does not always happen; some merle dogs have two dark eyes, though close examination may show a fleck of blue coloration.

Merle Gene Mapping: 

The 2005 mapping of the merle gene using 50 Shetland Sheepdogs not only tells us what genetic mechanisms produce merle genetics but also that merle is the same in all breeds.  

 Dr. Clark and her colleagues explain the merle gene mapping phase of their work in Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog as follows 

(We) carried out a whole-genome scan using the Shetland Sheepdog and were able to map the merle locus… To determine whether the SILV mutation causing merle patterning in the Shetland Sheepdog population was breed specific, merle and nonmerle dogs representing six other breeds (Collie, Border Collie, Australian Shepherd, Cardigan Welsh Corgi, Dachshund, and Great Dane) were analyzed for the insertion. Merle dogs from all six breeds were heterozygous and one double merle Great Dane was homozygous for the insertion.

Merle Gene Influence on Eye Color AND Its Influence on Ear & Eye Abnormalities in Double Merles:

Both blue merles (homozygous, for black & tan) and sable merles (homozygous for sable, as well as heterozygous for sable) have random chances for pigmentation in the eyes. The same genetic information mechanism involving mutations in the length of the “A” tail in the SINE that randomly puts merling spots on these collies also produces the following possibilities on eye color: both eyes brown; both eyes blue; one eye of each color; partial blue & brown in one or both eyes; and blue flecks in brown eyes. So while eye size, shape and set are genetically controllable through selective breeding, the presence of blue in the eyes of merles is not. While dark brown eyes would be the preference of most breeders & fanciers in both blue and sable merles, blue in eyes may or may not detract appreciably from the merle’s expression and is an individual matter of proper evaluation.

Below is the explanation for the relationship between pigmentation and its effect on normal eye and ear development from the Clark et al. paper Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog (bold below is mine):  

Melanocytes are pigment-producing cells present in many tissues, including the epidermis, hair follicle, inner ear, and choroid of the eye (33). Melanocyte cell populations differentiate from unpigmented melanoblasts released from the neural crest during embryogenesis (33). The complex process in which melanoblasts migrate and differentiate into melanocytes is not fully understood; however, the study of pigmentary anomalies may accelerate identification of genes important for normal development.

This research and prior work done by Dr. Sponenberg tells us that normal inner ear and eye development is, in part, controlled by presence of pigmentation. One copy of the merle gene causes no harm in the collie; however, two copies are a different matter. Fanciers and breeders call homozygous merle collies, those that receive a merle allele from each parent, by a variety of names, all of which describe the same collie: double merle, double dilution and white merle. These collies may have varying degrees of  vision and auditory abnormalities.

As Dr. Mike says, “Despite these defects, double merles may live normal lives. In fact, some are of superior conformation and when mated to non-merles have produced splendid Collies that are perfectly normal blue merles or sable merles, successful in the show ring and at performance events.” 

Again, the predisposition for abnormalities in double merles varies widely with some having both usable vision and hearing, some having one or the other, and some having neither. However, when a homozygous (two copies) merle is bred to a non-merle collie, the resulting offspring receive color/pigmentation from both parents but the merle allele from only the homozygous merle parent. All resulting puppies develop into blue merles or sable merles depending upon the base colors of each parent. These offspring will NOT have or produce any eye or ear abnormalities related to pigmentation since they only have one merle allele from the double merle parent and none from the non-merle parent. Their own merle offspring will also be normal.

Genetic Testing for the Merle Gene:

A genetic test for the merle gene will be available again soon and can give complete confidence that a dog is or is not carrying the gene. Nothing more than a simple cheek swab is needed from your collie – a non-invasive test. For more information, go to:

Normally, we know whether or not our collies are blue merles or sable merles.  However, there are some questionable situations that may arise. Cryptic merles are an example of a collie that may need genetic testing.

In phenotype (appearance) some collies can appear to be tri-colors or sables without  merle. However, these individuals may produce as merles because this is their genotype. If that happens, then a genetic test is in order. Furthermore, if there is any doubt at all as to whether a collie you own and plan to breed has a merle genotype, then testing prior to breeding is needed. Because of the probability of producing 25% double merles, merle to merle breedings would only be appropriate in very specific situations.


We’ve come full circle in our discussion of the collies’ beautiful colors and patterns. Genetics is an amazing and wondrous science with a great deal to teach us as breeders and fanciers. If we take the time to educate ourselves properly and make an effort to keep up with the latest that science has to offer, our beloved collies will be all the better for our knowledge.

Excellent quality sable merles, like excellent quality blue merles, sables, tri-colors and color-marked whites, have a great deal to contribute to the collie gene pool. Fear and misinformation should not stand in the way of what they have to teach us! As Dr. Mike explains, “There is absolutely no fundamental distinction between blue merle collies and sable merle collies other than the fact that blues, having inherited black & tan alleles, have diluted grey bodies with grey and black spots while sable merles have similar spots on sable bodies. The fact that a Collie is a merle, blue or sable, is simply an important characteristic to be noted, not one to be used to stigmatize it.”

“Continuity gives us roots; change gives us branches, letting us stretch and grow and reach new heights.” (P. Kezer) 

Author: Kathy V. Moll – Deep River Collies – My deepest appreciation for allowing me to interpret their research and for their technical assistance & editing to Dr. Leigh Anne Clark, Dr. Phil Sponenberg, & Dr. Mike Vaughan!


 Dr. Leigh Anne Clark TX A & M University  

Retrotransposon insertion in SILV is responsible for merle patterning of the domestic dog, by Leigh Anne Clark et al. was published in the National Academy of Sciences PNAS

Other interesting articles about sable merles may be found here:

6 Responses to SABLE MERLES

  1. Marguerite says:

    White in herding dogs is penalized because sheep do not feel pressured by white dogs and are more difficult to move. Marguerite

    I’m speaking to this point strictly from my own herding trial experience with an Advanced titled collie and as one who has bred and/or owned at least 10 collies with trial titles and many more with PTs. Sheep, cows & ducks respond to and feel pressured by dogs that cover & rate well. Samoyeds are eligible to compete in AKC herding because herding was one of their functions. I’ve seen a number of these ALL WHITE dogs command a great deal of respect from sheep and do a lovely job herding. Coat color has nothing to do with herding ability. Kathy

    This is universal throughout herding breeds with very rare exceptions. It has nothing to do with merling. Marguerite

    Please point to the reference in my article that says color headed white collies and sable merles have something to do with each other except as an illustration of a standard revision in 1977. No one sent a directive to judges about blue headed whites then as they are now about sable merles! They clarified the standard with a brief revision as is being advocated by some now. Kathy

    As described by the standard, sable merles are sable in color. No further clarification is necessary to anyone who has undertaken the most minimal level of breed education. Marguerite

    My “minimal level of breed education” apparently isn’t up to par with your own in-depth study. Please suggest how I might further educate myself. If there are any books or articles I haven’t read on collies and genetics, any seminars I haven’t attended, any practical experience I haven’t undertaken over the past 35 years, I really want to take advantage of them now!Kathy

    There is no need to change or clarify the standard; it says what needs to be said. Changing it will not change the minds of those who don’t like the color. Marguerite

    Liking or not liking sable merles has nothing to do with the article’s points. Some folks don’t like blues, whites, tris and even sables, but they’re IN the breed standard!Kathy

    The standard’s authors clearly understood that sables could inherit merle genes and that likely explains the requirement that a collie’s eyes be dark and matched in color, except for BLUE merles. I owned an exceptionally beautiful sable merle bitch who had two sapphire blue eyes. Beautiful, but unshowable. She had a twilight zone sort of expression, not very desirable. Matguerite

    Your decision, and a wise one under the current standard! Kathy

    Every 15 or 20 years, there is a brief but lusty debate about changing the standard to mention sable merles. So far, the vocal minority demanding the change has not been persuasive. I will hope that the standard remains unchanged; it is well written as it stands. Marguerite

    In fact, the one vote taken in the 1980s of the membership-at-large proved that the “minority,” vocal or not, favored standard revision – between 70% & 80% or so I was told at that time by the then CCA president. Fear of the general membership disagreeing with those who do not wish change seemed to be driving the resistance then as it is now. The vote was disregarded then; let’s hope that one is taken now! Asking the full membership to vote is all that is needed to put this question to rest. If those who do not favor standard revision are in the majority then so be it! I agree that the standard is a good one especially compared to some other breeds’; however a revision of a few words would hardly gut it – leaving 98% of it as it is. Kathy
    “A foolish consistency is the hobgoblin of small minds.” R. W. Emerson

  2. Marguerite says:

    My “minimal level of breed education” apparently isn’t up to par with your own in-depth study. Please suggest how I might further educate myself. If there are any books or articles I haven’t read on collies and genetics, any seminars I haven’t attended, any practical experience I haven’t undertaken over the past 35 years, I really want to take advantage of them now!Kathy

    There is no question that you have more than minimal knowledge of the breed. That was not my point. My point is that sable merles are sable in color, and that is not rocket science. I honestly do not see the point in changing the standard to state what is already obvious – sable merles are sable in color. The fact that a couple of trouble makers apparently decided to excuse a couple of sable merles from the ring because they were sable merles is not a good reason to change the standard. Frankly, this strikes me as dumbing things down for people who have trouble figuring out what color sable is. Marguerite

    I’m not sure that Shelley Roos excusing a rough from the Open Sable class in Dec. because it was a sable merle nor Pat Hastings withholding ribbons from someones collies because she said it was a sable merle & did not fall within the breed standard qualifies them as troublemakers. Since one is a lifelong collie person and the other a well known author and seminar presenter, I don’t think the “dumbing down” point is valid either. I know them both – and I don’t believe either has trouble knowing what brown coat color is. Kathy

    If wholesale quantities of sable merle dogs were being excused from the ring or passed over for awards, that would require some sort of action to correct judges perceptions of what is acceptable and/or desirable. Most judges look at sable collies as sable collies, whether or not they have a merle gene. They don’t care. Marguerite

    I’m afraid that my observations don’t support this idea either. My own active attandance at shows has allowed me to see first hand that there is quite a bit of discrimination – I and others have countless stories about judges in the double digits who have and still do discriminate.
    A large number care. Annie Rogers Clark wrote specifically in favor of discriminating against them just before she died a couple of years ago, which dramatically increased discrimination, IMHO. She was one of the best known all-breed judges in dog show history and based her arguments against them on the current words in our standard. I guess she joins Pat and Shelley as folks who are just too mentally challenged to see how clearly our standard includes them! Kathy

    Your proposed revisions don’t gut the standard, but I see no need to change a standard that seems to be working just fine. This seems to be change for the sake of change. Marguerite

    Again, your same argument was made when blue merles were added to the standard in 1950 and when blue headed/marked whites were included in the 1977 revision. I believe that both revisions clarified the standard and allowed intelligent breeders to feel secure in using more worthy collies in their breeding programs. The precedents have been set. This discussion has been going on for decades and needs settling.
    My fervent hope is that a vote by the entire membership will happen so that we will know once and for all whether the majority want to see the Standard Committee work on a revision. Kathy

    The only Marguerite I know of in collies is McGrath. Is that who I’ve been talking with? If so, I hope you won’t ask me to send back the artwork I’ve received as gifts and have purchased from you in the past! I really like it. 🙂 Kathy

  3. Sherry says:

    Simply amazing. With the number of All-Breed Collie approved judges out there who know the breed only through the “Standard”, you’d think more people would be up for a change which better clarifies a point they should be knowledgable of. What a relief from pressure it would be for me (if I were a judge) to know precisely what the acceptable is.

    We’re not talking about changing the standard to fit the dogs just because that’s what’s in the ring. Its about making clear TO EVERYONE what they’re saying is already allowable.

    The arguement to “leave it alone” could be applied back to the Blue Merle. Now that we know its really “just a black dog” with a merling gene, why keep a seperate class for them at all?

    And your proposed changes are so minimally invasive they’re hardly changes at all. They’re really just clarifiers. We’re not even asking for a class unto themselves. Just a clearer interpretation.

    I’m with you. People have to wake up and realize that if our beloved breed is to continue towards being the best it can be, then they’ll have to admit to the proven scientific data (and not be afraid to use it if they are breeders!) and allow that change is neccesary for the continued growth and betterment of the breed.

  4. sharon mayes says:

    Kathy, I could not agree more that the standard should be CLARIFIED. We are not talking about making huge changes to the standard – just clarifying it so that judges can feel comfortable awarding a deserving sable merle the ribbons. Clarification of any subject is always a good thing. As far as I am concerned we should celebrate the beautiful coat patterns of some sable merles and appreciate them as much as we can appreciate the beautiful and unique patterns on a blue merle. I think we who voted yes should have buttons or t-shirts made stating “proud to own and show a sable merle”! If the sable merle is good enough to be in a person’s breeding program then they should be good enough to be winning in the ring. Thanks for helping to champion this clarification of the standard.

    • Kathy says:

      Sherry & Sharon,
      We’re asking for clarification now from Tom, Bob & the SRC on all the double talk surrounding the survey/poll they just sent out. We’re also asking them about information that they are not planning to honor the ballot that was sent out according to our bylaws to the membership if the vote is “yes” rather than “no.” The legal ballot was the simple “yes” or “no” to a standard revision to recognize the sable merle.

  5. Jerrica says:

    Kathy thank you for posting this, it was a very well written and concise argument for the clarification of the Standard and I agree wholeheartedly with you that these small measures of change would do handlers and breeders and owners a world of good.

    I have a stunning rough sable merle bitch with a lot of flash and incredible length of head, expression and conformation. She has impeccable breeding and is a joy to own in every way. She definitely turns heads, we were mistaken for the BIS winning sable rough in the last show we attended for rally/obedience not too long ago! Two dark brown eyes, minimal face merling (most is through her coat and only seen underneath when the topcoat is blown or lifted up) – she really looks to be a pure for sable to most who don’t look closely at her silver dusted ears).

    Were it not for a few unfortunate issues with her bite (occlusions, sadly) and being a touch too tall (25″), I would have asked to keep her intact and finish her. But with all the current issue of coat and whether it can finish in the ring in addition to her unfortunate dentition (perfect teeth as a puppy, darn it), I just spayed her. She’s my performance girl through and through – herding tested, CGN, does therapy with me, one leg from her CD, starting rally excellent now and she is making waves in agility too.

    I was wondering if any less desirable traits link with the dilution gene? That would be my only concern with having a sable merle used for breeding. I haven’t seen any research or evidence of this being the case (though personally I have noticed a predisposition to being slightly taller/larger in the SMs I have seen – which in the era where many are becoming smaller, is not necessarily a bad thing either!)

    Either way in my opinion, the only good reason not to alter the Standard would be if the changes would cause a loss of quality in the breed. There seems to be no evidence this would be the case as many SMs are used in breeding quite extensively with excellent results in the show rings and performance rings through their beautifully put together offspring.

    Any good breeder worth their salt is going to be tremendously careful to ensure they keep only the best in their program – no matter the color. Changing the Standard to include sable merles will not change anything if they continue to be rigorous about which dogs meet that criteria. It just adds a bit more in terms of possibilities for the dogs available that may meet that criteria recognized through our Standard.

    Either way I don’t see any legitimate reason not to clarify the Standard for all of us.

    Truly, it would give judges peace of mind when a truly exceptional sable dog with merling comes their way, and handlers/owners/breeders a breath of relief if we had a lovely SM we wished to show and/or breed in the future. Not everyone will favor the look but that isn’t what the Standard is meant for anyhow any anyone who shows know we all have our subjective tastes and preferences for type and style.

    The Standard being changed won’t alter much besides allowing the dogs we know and love dearly to be judged more effectively when they happen to be sable merle.

    The Standard is simply the reflection of ideal and what good breeders should base their breeding goals and directions towards achieving along with an excellent program of assessment and health evaluation, temperament testing and working ability, in my opinion. Reading the Standard for AKC collies as stands now, it reflects a progress away from sable merles. And I regret that; as I have an extreme fondness for dark eyed sable merles such as my young lady here and would be thrilled to show one at a later date were the Standard to be changed as it should.

    I may still even with the Standard as it is now should a worthy pup come my way. It just makes me sad to see a truly exceptional dog turned away for something so trivial as this.

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