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Silver Lab Controversy

Coat Colors in Labradors

1. Basic Genetics and Inheritance Patterns 
2. Standard Coat Color Genetics in Labradors
3. Unusual Coat Variations in Labradors
4. History and Genetics of Dilute Coat Colors in Labradors
5. Health Problems in Dilute Labradors
6. The Silver Labrador Controversy 

1. Basic Genetics and Inheritance Patterns

Chromosomes are thread-like strands of DNA and protein that are found in the nucleus of cells. Genes are units of inherited material that are located on chromosomes. These small sections of DNA code for specific traits or cellular functions. Alleles are variations of a gene that control a characteristic or trait. One allele is inherited from each parent. Some alleles code for normal variations of the trait and others are associated with inherited disorders. For example, different alleles code for eye color, hair color, blood group types, color blindness, Tay-Sachs disease, and Cystic Fibrous. 

Mutations are permanent changes in a gene. These changes are transmitted to future generations. The frequency of spontaneous mutations is relatively low. Only a small percentage of them are associated with abnormalities. Some mutations results in beneficial traits and others are not associated with noticeable changes.

 Alleles can be dominant, co-dominant, incompletely dominant, or recessiveA dominant allele will be expressed if the individual has a single dominant allele. For example, in humans, a widow's pick hairline is dominant to a straight hair line. Huntington's disease is caused by a single copy of an abnormal dominant allele. If the alleles are co-dominant, both alleles will be expressed. The human blood group AB is a good example of co-dominant gene expression. Wavy hair in humans is an example of incomplete dominance. The offspring of a parent with curly hair and a parent has straight hair will have wavy hair. Traits controlled by recessive alleles are only expressed if the individual inherited recessive alleles from both parents. For example, the allele for blue eyes in humans is recessive to brown eyes. 

Inherited disorders are often caused by abnormal recessive alleles. Affected individuals inherit 2 abnormal alleles, one from each parents. Unaffected carriers have one normal dominant allele and one abnormal recessive allele. 

2. The Genetics of Standard Coat Colors in Labradors

"The Labrador Retriever coat colors are black, yellow, and chocolate. Any other color or combination of colors is a disqualification. A small white spot on the chest is permissible, but not desirable. White hairs from aging or scarring are not to be misinterpreted as brindling. Black- Blacks are all black. A black with brindle markings or a black with tan markings is a disqualification. Yellow-Yellows may range in color from fox-red to light cream with variations in shading on the ears, back, and underparts of the dog. Chocolate-Chocolates can vary in shade from light to dark brown. Chocolates with brindle or tan markings is a disqualification." AKC Labrador Retriever Breed Standard 

The genes that control the basic coat color in Labradors are located on 3 separate chromosome sites known as the B, D, and E loci. Alleles at the B-locus and E-locus are responsible for the black, chocolate and yellow coat colors if the dog has at least on dominant D allele at the D locusThe dominant B allele codes for the black coat color. The recessive b allele that codes for the brown coat color. 

The E locus alleles control the expression of the coat color alleles on the B locus. Black Labradors have at least one dominant B allele and at least one dominant E allele. Chocolates have 2 copies of the recessive b allele and at least one dominant E allele. The recessive e allele is a result of a mutation of the E gene. Labradors with 2 copies of the recessive e allele will be yellow. In these dogs, black and brown pigment production is prevented.  

3. Unusual Coat Variations in Labradors 

In Labradors, alleles at the A and K loci code for traits that are rarely observed. These alleles associated with several unusual coat patterns, including brindling, tricolor patterns, black and tan points, and long coats. 

These rare coat markings and patterns are not associated with inherited heath problems. These dogs are purebred, but they can not be shown and they should not be bred. These dogs usually make wonderful canine companions.

4. The History and Genetics of Dilute Coat Color in Labradors  

The dilute d allele in dogs is a result of a mutation of the D allele. Two recessive d allele at the D locus code for dilute coat color expression. The d allele has been in the canine gene pool for many years. It is absent or rare in some breeds, and common in others. All Weimaraners and Solvakian Pointers have 2 copies of the dilute allele. All dilute Labradors have 2 recessive d alleles. Initially, the d allele was probably absent in Labrador breed. 

The Labrador Retriever breed was developed in the early 1800's in Great Britain. The ancestors of the Labrador Retriever, St. John's Water dogs or Lesser Newfoundlands, were imported from Newfoundland. There is no indication that the St. John's Water dogs carried the dilute allele. In the 1800's, crossbreeding these dogs with other retriever breeds was probably done with the hope of adding desirable traits to their lines. Once the breed was established, the practice of crossbreeding was discontinued. No dilute offspring were observed in Great Britain until dilute Labradors were imported from America. 
  • The early Labrador breeders in Great Britain were known for keeping accurate, detailed records. Although the breeders in the 1800's and early 1900's preferred black Labradors, there is documentation of rare brown and yellow puppies. The first 2 brown Labradors were noted in 1892 and the first yellow Labrador arrived in 1899. Labradors with rare traits such as long-haired coats, black and tan markings, brindle patterns, and several other rare traits were also observed in Great Britain after the Labrador breed was developed. The genes for these rare coat patterns and markings were probably present in the St. John Water dogs in low numbers they may have been a result of crossbreeding these dogs with other breeds in the mid 1800's. Puppies with undesirable colors and markings may have been culled, but their birth would have been documented by these breeder. 
  • None of the meticulous records kept by these breeders indicated any dilute colored puppies. Initially, the first few generation of St. John's Water dogs were probably line bred to relatives other than parents or siblings. This practice increases the probability of an offspring inheriting recessive alleles from both parents. The Labrador gene pool was small in the early to mid 1800's. Both line breeding practices and the small gene pool would have increased the probability of produce dilute offspring if the early Labradors carried the d allele. No dilute puppies were observed. 
  • If the d allele was present in the early lines of black Labradors in Great Britain, the first dilute Labradors probably would have been charcoal puppies born in England. They were not. In the 1900's, the breeders in Great Britain focused on producing black Labradors. Chocolates were very rare, and many breeders considered them undesirable. Charcoal Labradors have at least 1 dominant B allele and 2 dilute alleles that alter the normal black coat color. The resulting is a dark coat with a slight metallic sheen. The first dilute Labradors arrived in USA in the mid 1900's, and they were gray. Gray or silver Labradors have 2 chocolate b alleles and 2 recessive d alleles. Two dilute alleles change the normal brown color to a shade of gray. The first dilute puppies born in England were born in 2006 to silver parents imported from America.
  •  The d allele was probably not present in the Labradors in Great Britain in the 1800's and 1900's. Occasionally, rare recessive alleles have been known to remain hidden for many years. It's possible, but very unlikely, that the d allele could have remained hidden for more than 100 years.
Dilute breeders believe that the d allele has been the Labrador gene pool all along even though there is no indications that the d allele was in the gene pool of the English Labradors is the mid 1800's and 1900's. All dilute Labradors have been traced back to 2 dogs breed at the Kellogg kennels in the mid 1900's- Kellogg's Nick and Kellogg's Kernel. 
  • It's possible, but unlikely, that a Labrador imported from Great Britain carried both the chocolate b and d allele. The popularity of chocolate Labradors increased in America in the mid 1900's, and that may have resulted in an increase in the number of Labradors that carried the d allele. If the d allele was in the British lines imported to America, the silver puppies born at the Cull, Beaver Creek, and Kellogg kennels could have been purebred Labradors. It is very unlikely that this sequence of events took place.
  • Another possible source of the d allele is a spontaneous mutation in the D allele in the chocolate Labrador lines in the USA in the 1900's. However, the d allele in dilute Labradors is genetically identical to the d allele in Weimaraners. The type of mutation that would alter the D allele is a rare, random event and it's extremely unlikely that a random mutation would to be duplicated. 
  • Crossbreeding a Labrador with a dilute dog, or one that carried the dilute d allele, is the most likely source of the dilute allele in the Labrador breed. All Weimaraners have 2 copies of the dilute allele. (Chesapeake Bay Retrievers also carry the d allele.)  The initial crossbreeding event could have been accidental. A dog that carried the dilute d allele may have "jumped the fence". It's also possible a crossbreeding with a dog that carried the d allele was planned with the hope of adding new traits to their lines. The Kellogg kennel advertised pointing Labradors. It's noteworthy that the HPR trait (hunt point retriever) is common in Weimaraners, and had not previously been observed in Labradors. The Culo, Beaver Creek, and Kellogg kennels actively bred silver Labradors. Close inbreeding the early silver Labradors with siblings, cousins, and parents increased the numbers of Labrador that were silver or carried the dilute trait in these kennels. 
The AKC investigated the silver Labradors at the Culo Kennels in 1987.
  • The sire and dam information supplied by the early breeders of silver Labradors must have indicated that their dogs were purebred Labradors. The registration of purebred dogs is primarily based on the honer system. 
  • Based on the pictures and the appearance of the silver Labs there were probably no obvious"red flags" during the AKC's investigation. Pictures of the dilute dogs were also studied. Weimarraners and Chesapeake Bay Retrievers are about the same size as a Labrador, and their overall appearance is similar to Labradors. If the dilute allele was a result of crossbreeding a Labrador with a Weimarraner (or Chesapeake Bay Retriever) in the mid 1900's, the silver Labradors observed in 1987 probably resembled purebred Labradors. 
  • "In 1987 we conducted an inquiry into the breeding of the litter that contained the dogs that were registered as silver and one of our representatives was sent to observe several of the dogs that had been registered as silver. Color photographs of these dogs were forwarded to the office of the American Kennel Club where the staff of the AKC and the representative of the Labrador Retriever Club of America examined them. Both parties were satisfied that there was no reason to doubt that the dogs were purebred Labrador Retrievers, however both parties felt that the dogs were incorrectly registered as silver. Since the breed standard describes chocolate as ranging in shade from sedge to chocolate, it was felt that the dogs could be more accurately be described as a chocolate than as silver." Robert Young  of the AKC  
All claims that there has been extensive testing that proves that silver Labradors are purebred FALSE!  
  • Canine DNA parentage tests was not available in 1987 when the AKC investigated the silver Labradors. 
  • Before these testing procedures were available, AKC investigations were based on inspections and the review of pedigrees and pictures of the dog or dogs in question. 
  • Pictures and pedigrees can not prove or disprove the purebred status of a dog. 
The decision to register dilute Labradors was NOT BASED ON SCIENTIFIC EVIDENCE. 
  • The American Kennel Club made an "educated guess" based on their trust in the accuracy of the pedigrees and pictures of dilute dogs they reviewed in the 1987 investigation.
  • The AKC did not conduct any DNA testing in 1987. They registered litters based on the registration status of the sire and dam. 
  • The DNA parentage tests needed to determine the accuracy of the pedigrees of early dilute Labradors were developed after the AKC made the decision to register silvers as chocolates, charcoals as blacks, and champagnes as yellows. 
  • There are no DNA samples from the first gray/silver Labs bred at the Kellogg, Culo, or Beaver Creek Kennels in the 1900's that could be tested to determine the parentage of the first silver Labradors. 
  • Today, the sire and dam of a puppy can be verified using accurate DNA parentage testing procedures.

THE SOURCE OF THE DILUTE ALLELE IN LABRADORS IN UNKNOWN AND IT WILL REMAIN A MYSTERY!  Canine DNA parentage testing procedures were developed several years after the first dilute Labrador puppies arrived. Without testing DNA samples from the sires, dams, and the first dilute puppies born in the mid 1900's, it is impossible to determine the source of the dilute d allele and the purebred status of dilute Labradors. 

5. Health Problems in Dilute Labradors

Labradors with dilute coat colors may experience inherited health and behavior problems. 

  • Coat Dilution Alopecia is an inherited disorder that can cause severe hair loss and reoccurring skin infections in dilute Labradors with a faulty form of the d allele. 
  • Some additional inherited problems associated with dilute Labradors include von Willebrand's, hyperuricosuria, and separation anxiety.  

6. The Silver Labrador Controversy

The dilute breeders believe their lines are purebred, and mainstream breeders disagree. Neither side is likely to change their position. Dilute breeders deny that the addition of the d allele could have been a result of crossbreeding a Labrador with a Weimaraner or another breed that carries the d allele.  Most mainstream Labrador breeders support the theory that dilute allele was introduced into the breed when a Labrador was crossbred with a dog that carried the d allele, probably a Weimaraner, in the early to mid 1900's

"It is the opinion of the LRC that a silver Labrador is not a purebred Labrador. The pet owning public is being duped into believing that these animals are desirable, purebred, and rare and therefor warrant special notoriety or a premium purchase price." Francis O. Smith, DVM, PhD

There is no scientific method that can verify that the dilute Labradors are purebred or a result of a crossbreeding event. The dilute breeders that claim that silver Labradors are purebred are misinformed and/or they do not understand genetic testing procedures. The AKC accepted the pedigrees supplied by the early dilute breeders before DNA testing was available, and they will continue to register dilute Labradors as purebred dogs based on the pedigrees. Current dilute breeders probably believe the inaccurate and false statements made by the early dilute breeders regarding the extensive research and testing that proves that dilute Labradors are purebred. Unfortunately, the claims made by dilute breeders regarding the purebred status of their dogs are an ongoing source of concerns.

"The Labrador Retriever coat colors are black, yellow, and chocolate. Any other color or combination of colors is a disqualification."  AKC breed standard

Regardless of the purebred status of dilute Labradors, dilute colors are not acceptable Labrador coat colors based on the well established breed standard. Charcoal is not black! Silver is not chocolate! Champagne is not yellow! Breed standards describe in detail the appearance, temperament, movement, desirable traits, and disqualifying characteristics of  breed. These standards serve as a guidelines for breeders as well as a valuable reference for potential dog owners looking for the dog that will be suitable for their lifestyle. Breeders that follow the standard ensure that the qualities described in the standard will be preserved. Labradors with dilute coats, black and tan markings, brindle patterns, the Dudley nose, or long-haired coats have disqualifying colors and markings. 

The AKC does not recognize the dilute colors. They registers dogs base on their parentage, so dogs with disqualifying coat traits and colors can be registered. Dilute breeders utilize AKC's policy of registering dogs if both parents are registered Labradors. The dilute offspring are registered as black, chocolate, or yellow based on the color the dogs would be if the dog had at least one dominant D allele.

Responsible, ethical Labrador breeders are dedicated to the betterment of the breed. Reputable breeders do not promote disqualify traits or other known genetic problems in their breeding programs. These breeders focus on health, temperament, structural integrity, intelligence, conformation, working ability, and the classic Labrador temperament. They avoid all disqualifying traits in their breeding programs. If a mainstream breeders has a puppy with disqualifying markings or coat color, the puppy will be placed in a pet home with limited registration and/or a spay/neuter agreement. 

Dilute breeders promote disqualifying coat colors. When breeders fail to follow the breed standard or focus on a specific trait (for example the dilute factor), the overall quality of the offspring is often decreased. Ethical, responsible breeders do not breed dogs with disqualifying colors or markings, especially for monetary profits. DNA testing that identifies dogs that carry the dilute allele is now available, and many responsible breeder have their Labs tested. Since ethical breeders will not breed their Labradors with dilute dogs or a known carrier, the overall quality of the dilute Labrador gene pool may be compromised. For many years, dilute Labradors were a result of inbreeding and close line breeding  practices. However, recent research indicates that the gene pool of silver Labradors is now more diverse, and the genetic risks associated with inbreeding have been reduced. 

Most mainstream Labrador Retriever breeders think the dilute breeders:
  • Disrespect the Labrador breed standard
  • Make false claims regarding extensive testing that proves dilute Labradors are purebred
  • Focus on financial gain rather than the betterment of the breed 
  • Sometimes promote overpriced puppies as rare and unique 
  • Have a questionable code of ethics