Pamela A. Davol, 76 Mildred Avenue, Swansea,
MA 02777-1620
pdavol@labbies.com
Updated and Revised for 2001
Reprinted from an e-mail
The AKC Stand on Registration of Silver Labradors:
Response of Jack Norton of the AKC on 1/24/00 giving AKC official position on the issue of Silver Labs.
The registry of the American Kennel Club is based on parentage and not the coat color of a member of any breed.
In 1987 the AKC, in corporation with the Labrador Retriever Club of America, conducted an inquiry into the breeding of litters that contained members that were registered as silver. An AKC representative was sent to observe these dogs. The report and color photographs of these dogs were reviewed by AKC staff and representatives of the Labrador Retriever Club of America. Both Parties were satisfied that there was no reason to doubt that the dogs were purebred Labrador Retrievers, however they felt that the dogs were incorrectly registered as silver. Since the breed standard at the time described chocolate as ranging in shade form sedge to chocolate, it was felt that the dogs could more accurately be described as chocolate rather than silver. This remains the current policy of the American Kennel Club.
Jack Norton
Special Services Dept
There is no such thing as a silver Labrador.
False. This is really more an argument based on semantics and upon which most conflicts regarding the silver color in the breed are based. Silver Labs do exist here and now, however, history records of the Labrador breed strongly support the conclusion that the silver color was introduced sometime in the mid-history (between the 1940s - 1950s) of the Labrador breed (see below for discussion of origins). For this and other reasons, the trait is not considered as being representative of the breed.
The silver coat color has been recorded in early writings about Labradors.
False. There is no record of "silver", "gray" or any other color that could be construed as silver between 1878 and 1948 (i.e. the early history of the breed) in the breed stud books. Reportedly, a Norwegian Elkhound cross was performed sometime in the 1940s which coincides with subsequent European reports of "silver" Labradors appearing in some lines during the 1950s and 1960s (see below for more information).
The small gene pool in the early history of the breed had made it difficult to select for silver because "there was never a large enough gene pool of other grays to replicate the color."
False. It is a well established principle of genetics that the smaller the population (i.e. gene pool) the more likely for the offspring of the population to express traits associated with recessive genes.
Genetic analysis has demonstrated that the gene responsible for the silver coloration in Labs is mapped to a site different from the site responsible for the silver color in other breeds of the dog.
False. There is currently no scientific data, either published or preliminary, which has mapped the silver gene locus in Labs. Scientists at the University of California, Berkeley, are, however, currently conducting pedigree analysis on silver bloodlines to determine origins of the silver coloration.
The observation that general breeders of Labradors have not accepted the challenge to disprove the purity of Silver Labradors is confirmation that the bloodlines are pure.
False. General Lab breeders have consulted with geneticists on the feasibility of performing genetic analysis on the silver Labradors. Current DNA technology is, ironically, too specific a method for assessing genetic relationship between silver Labs and the general Lab population. Although parentage can be determined by DNA testing, there exists too much genetic diversity even between related Labrador bloodlines, which limits the ability of this method to prove or disprove the degree of relatedness between silver Labs and the general Lab population.
Silver puppies born of purebred, AKC registered Labrador parents should be destroyed to preserve the breed.
False. The silver coloration is considered a serious fault in the breed, however, it does not alter the health or disposition of the dog. Therefore, it is recommended that silver puppies produced by registered Labs be placed in pet-homes without AKC registration papers or with Limited Registration to prevent further propagation of the silver gene.
This is one of the most common questions voiced by the public. Commonly the answer is provided that " the silver Labrador is not a Labrador at all because it is a product of crossbreeding (interbreeding)." This statement may hold both truth and fiction.
Some individuals may argue from the point that up until a few decades ago, the chocolate Lab was, indeed, a minority with many people doubting the genetic integrity of the chocolate coloration. In bench competition, chocolates were often disqualified from competition and even in recent years the chocolates still are considered disparagingly among some Labrador enthusiasts. However, the "liver" (chocolate) coloration appears in most of the retriever breeds and also appears in the original ancestors of the Labrador. In support of this, records of early breedings, around the late 1800s, confirmed that livers were occasionally whelped to black Labs.
Though it is suspected that the yellow coloration was the product of interbreeding, yellow Labradors have been around since the breed was originally accepted as a purebred dog. Therefore, the yellow coloration, though foreign to the original ancestors of the breed (since no yellowed-colored water dogs, only black and occassionally liver-colored, were ever documented as arriving from the breed's country of origin, St. John's) was recognized as an acceptable trait in the Labrador.
So, what of silver? Given the fact that much inbreeding was performed during the early history of the breed because of the small gene-pool, expression of the silver trait would have occurred at least frequently enough for someone to take note of its existence. This was, indeed, the case with the expression of the "black and tan" trait. Early history cites cases of puppies born with tan points (as found in Dobermans, Rottweilers, etc.). This trait was attributed to early interbreeding with Gordon Setters. There is no record, however, of silver Labs or any similar color documented in the stud books spanning the years 1878 to at least 1948 (though other color oddities are documented). This strongly suggests that the silver color is not a color that was present (indigenous) in the early ancestors of the Labrador breed. Therefore, the color must have been introduced sometime after the 1940s. The instances of silver Labs appearing, albeit rarely, in litters from the general population that bear no common ancestors within several or more generations suggests that the gene has been in the population for quite a few decades (This does not necessarily rule out the possibility of more recent interbreeding to purposely achieve or increase frequency of expression of the color). As such, possibilities for the origin of the silver gene may include, but are not limited to the following: 1) a spontaneous gene mutation, or 2) mid-history introduction of the silver gene through interbreeding with a breed carrying the silver gene.
Spontaneous gene mutations occur frequently within any given population. Conceivably a change, most likely in the melanin-stimulating-hormone receptor (Mc1-r) encoded by the Extension Locus (E), could result in a dilution of eumelanin (black/brown pigment) synthesis in Labradors inheriting this mutation and lead to expression of a charcoal or silver coat. Mutations of the Mc1-r have been reported in canines, including the Labrador, and other species (see B/b, E/e, and Beyond: A Detailed Examination of Coat Color Genetics in the Labrador Retriever). Characterization of the Mc1-r in these silver Labs may provide some clues to support or deny spontaneous mutation events as a potential cause for this coloration. To my knowledge, however, no such studies in regard to silver Labs are currently being conducted.
In regard to interbreeding, it is important to understand that purebred development was frequently based upon crossing one breed with a different breed to bring in desirable traits from that different breed. (i.e. introducing "foreign" genes). Through careful breeding programs, early breeders were able to select for the desirable traits of the "foreign" dog while breeding out the other obvious, non-standard traits characteristic to the "foreign" purebred. Mary Roslin-Williams, in her book All About the Labrador, describes a prime example of this, which may have direct implications regarding the origin of the silver Lab phenotype. In her book, she makes reference to a Norwegian Elkhound/ Labrador crossbreeding occurring in the 1940s, as well as to Pointer/Labrador crossbreedings occurring in some field lines. Generally speaking, one may recognize why frequent, widespread crossbreeding, especially in inexperienced hands could cause considerable problems within any breed. However, not all instances of this practice should be viewed negatively. In fact, from a genetic standpoint, there are many positive arguments for the occasional, but controlled use of interbreeding (refer to: Purebred Dog Breeds into the Twenty-First Century -- Achieving Genetic Health for Our Dogs by Dr. J. Jeffrey Bragg). In regard to the Labrador, it is important to recall that at that time, the yellow Labradors were devoid of type, appeared houndy-looking, and had no undercoat to speak of. Crossbreeding of the Norwegian Elkhound offered a quick means of introducing the correct undercoat. Furthermore, the two breeds were similar in terms of structural build. Indeed, this crossbreeding, which may have been one of the key factors leading to improvement of "type" in yellow Labs, may also provide another explanation of how the silver phenotype was introduced into the breed: the silver gene found in the Norwegian Elkhound.
Some purists may be alarmed by this information, however, from a genetic standpoint, the selection and cultivation of "Labrador traits" and the elimination of traits foreign to the breed over subsequent generations has assured the genetic integrity of breed as being "Labrador", even in the presence of such historical crossbreeding. However, one may understand the importance and necessity of a breed standard for ensuring a general consistency among individuals of the breed. As with other traits that are a throw-back to early interbreeding, such as the black-and-tan (attributed to early interbreeding with the Gordon Setter), breeders concerned with maintaining the original attributes of the breed recognize these traits as being associated with the remnants of past crossbreedings. Additionally, to maintain a general consistency within individuals of the breed, selection against undesirable traits, whether they are due to "spontaneous mutation" or "foreign" genes introduced by selective crossbreeding, is maintained. It is for this reason that we rarely see evidence of "foreign" genes in the Labs of today.
Canine genetics is a fascinating area of science. Experimental interbreeding performed by early researchers like Little and Whitney provided many answers to modes of inheritance of many traits including but not limited to coat color. Such purposeful interbreeding was carried out to increase breeders' knowledge and therefore assist them in producing better pure-bred dogs. But what exactly is a better pure-bred dog? Because opinions and tastes may vary widely from one breeder to the next, if left to the individual breeder, one particular breed could become so diversified that members of that breed may look and act nothing like other members. That is why the American Kennel Club, working with the breed parent club, sets the standard for each breed. The standard describes physical and temperament characteristics which are inherently typical of a dog of that particular breed and therefore serves as a guideline for breeders.
As with early breeders who cultivated the traits of the Labrador breed through careful propagation of desirable traits and elimination of faults through selective breeding programs, breeders today follow the breed standard to ensure that the qualities of the breed are preserved. Therefore, at this time, traits such as black and tan, brindling, and silver coloration are considered serious faults of the breed and purposeful selection of these traits for breeding purposes is not recommended. Additionally, the American Kennel Club recognizes only Labradors which are black, chocolate, or yellow. The AKC standard for the Labrador specifically states: "The Labrador retriever coat colors are black, yellow and chocolate. Any other color or combination of colors is a disqualification."
As with any Lab, temperament and type will depend on the bloodlines of the dog regardless of color. Depending on the breeding lines, a silver Lab can make just as lovely a companion dog as a Lab of any other color. However, as with any Lab that may express an undesirable hereditary trait, a silver lab should be placed in a pet home without registration papers or with Limited Registration to ensure that the fault is not passed to offspring.
The origin of the silver coloration in Labradors remains uncertain at this time. For the AKC to recognize the silver coloration, the parent club would first have to rewrite the standard and vote to accept the silver coloration. For the first of these situations to happen, the silver Lab would have to gain support among a number of its parent club members (as the yellow coloration once had its enthusiastic supporters back in England during the early days of the breed). This scenario is most likely not to happen in the near future. As such, breeders, either established or novice, who may consider breeding for silver will most likely find many doors closed to them in terms of breeding to the best Labrador bloodlines. As such, there are many factors (of which the true origin of the silver is just one) to take into consideration before a breeder or owner should consider the silver colored Lab.
Research Contacts: Any breeders who have produced silver-colored
puppies and would like to assist in the research of the silver-coloration are invited to
contact Dr. Neff at: neff@uclink4.berkeley.edu. All contacts and information will
be handled confidentially.
Related links (**please note: reference to the following sites should not
be construed to mean that this author agrees with the conclusions or content of either
site**)
Crist Culo Kennels: Breeder of Silver Labs
Possible gene loci that may cause the silver coloration are discussed at: B/b, E/e, and Beyond: A Detailed Examination of Coat Color Genetics in the Labrador Retriever
References:
Cornell University Animal Health Newsletter, "Coat Color Inheritance," Volume 14, Number 11, January 1997.
Suzuki, D.T., Griffiths, A.J.F, and Lewontin, R.C. (eds.), An Introduction to Genetic Analysis,San Francisco, W.H. Freeman and Co., 1981.
Helen Warwick, The New Complete Labrador Retriever, New York, Howell Book House, Inc., 1986.
Helen Warwick, The Complete Labrador Retriever, New York, Howell Book House, Inc.,1965.
Leon F. Whitney, DVM, How To Breed Dogs, New York, Howell Book House, Inc., 1972.