This pattern should NOT be added to any other dog breeds. It is a risky and dangerous mutated gene. The approved breeds below should be the ONLY breeds to have this pattern and those breeders need to do their due diligence to safely work with this gene. Those breeders should also test for eye and hearing issues, they should research how to handle the mutated gene, and proceed with caution. This pattern is BANNED in many countries and it has nothing to do with the color/pattern but HEALTH!
Merle is a distinguishing marking of several breeds, particularly the Australian Shepherd, and appears in others, including the Koolie, German Coolies in Australia, the Shetland Sheepdog, various Collies, the Welsh Corgi (Cardigan), the Pyrenean Shepherd, the Bergamasco Sheepdog, the Old English Sheepdog, and Catahoula Leopard Dog.
In Dachshunds the merle marking is known as "dapple".[6] It is also present in the Pomeranian and Chihuahua, but is a disqualification according to the FCI standards. The merle gene also plays a part in producing harlequin Great Danes. In several breeds, such as the Pomeranian and Chihuahua merle is an indicator of cross breeding.
The merle pattern has been incorrectly linked to pure bred the American Pit Bull Terrier (APBT). Historically it was not found in the breed, and is likely the result of southern breeders cross breeding the American Pit Bull Terrier with the Catahoula Leopard Dog.[7] It is considered a genetic flaw and the ADBA and UKC do not accept registration of APBT with the merle pattern.[8][9]
SOURCE: http://en.wikipedia.org/wiki/Merle_%28dog_coat%29
Merle is a distinguishing marking of several breeds, particularly the Australian Shepherd, and appears in others, including the Koolie, German Coolies in Australia, the Shetland Sheepdog, various Collies, the Welsh Corgi (Cardigan), the Pyrenean Shepherd, the Bergamasco Sheepdog, the Old English Sheepdog, and Catahoula Leopard Dog.
In Dachshunds the merle marking is known as "dapple".[6] It is also present in the Pomeranian and Chihuahua, but is a disqualification according to the FCI standards. The merle gene also plays a part in producing harlequin Great Danes. In several breeds, such as the Pomeranian and Chihuahua merle is an indicator of cross breeding.
The merle pattern has been incorrectly linked to pure bred the American Pit Bull Terrier (APBT). Historically it was not found in the breed, and is likely the result of southern breeders cross breeding the American Pit Bull Terrier with the Catahoula Leopard Dog.[7] It is considered a genetic flaw and the ADBA and UKC do not accept registration of APBT with the merle pattern.[8][9]
SOURCE: http://en.wikipedia.org/wiki/Merle_%28dog_coat%29