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Historically Non-Merle Breeds that have had the Merle Pattern added to their Gene Pool
Trait not Allowed in Their Official Standard

The following breeds have had the Merle trait introduced by way of an outside breed after the stud book was closed.
A closed stud book does not allow for the addition of outside blood/breeds. All dogs qualifying for registration are descended from the original foundation stock.

The addition of the Merle trait has been accomplished through fraudulent/falsified pedigrees (hung papers) at some point (either once or multiple times) in the breed's history. This is achieved when a breeder registers a litter using a false sire and/or dam's name and registration number.
Many of the breeds listed here have had the Merle trait in the gene pool for 10, 20, 30 years or more, and through back crossing to the original breed population, now exhibit the standard physical traits of that breed in all ways except the addition of a pattern that was not historically ever found in the breed.

Typically, these dogs consistently show a 100% match with their breed when tested using services like Embark or Wisdom Panel, which specialize in breed identification. This is because the introduction of an outside breed occurred multiple generations back. In these cases it is very important to note that "Purebred Status" and "Genetic Ancestry" are completely separate concepts.
"Purebred" status is defined by pedigrees at registration bodies whereas "Ancestry" looks at segments of shared DNA.  

The Working Kelpie
breed gets a special mention here - the breed standard does not allow for the merle trait and a visible merle pattern is not seen in the breed. However the foundation dogs used in the development of the breed included historic merle breeds so the non-expressing alleles of Mc and Mc+ do still exist in the breed.

American Bulldog

American Pit Bull Terrier

American Staffordshire


Biewer Terrier


Boston Terrier

Bull Terrier

Cane Corso

Cavalier King Charles Spaniel

Chow Chow

Cocker Spaniel

Doberman Pinscher

English Bulldog

French Bulldog

German Shepherd

Miniature Schnauzer



Rat Terrier

Siberian Husky

Yorkshire Terrier