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What Is a Double Merle?
Double Merles are 100% preventable!

What Is a Double Merle?


Double Merle (Homozygous Merle) is the common term for a dog with two copies of the Merle gene. Double Merles are a result of bad breeding practices, most commonly known as spot x spot breeding. For Great Danes, this could be Harlequin x Merle, Harlequin x Harlequin, Merle x Merle, any Quin x Quin, or any Quin x Merle breeding. When we say Quin x Quin, we are speaking of Harlequins, Merlequins, Brindlequins, Fawnequins, etc.

On every spot x spot litter, each puppy within the litter has a 25% chance of being born a Double Merle. Double Merle dogs are highly likely to suffer from hearing and vision impairments and, in some cases, complete blindness and deafness. Deafness and hearing impairment happen due to a lack of hair pigment in the inner ear. Double Merles can also be blind or have vision problems due to congenital eye defects. Double Merles are often partially or completely white in coat color, sometimes referred to as albino, though that is an entirely inaccurate statement.

Double Merles are NOT albinos! In Double Merles, the white coat is produced by doubling up the gene responsible for the Merle gene (the Merle gene is a bleaching pattern, not a color). Their coat pattern is characterized by light-colored fur and irregular spots. Merle makes melanin pigmentation less intense in random areas of the dog's body. Keep in mind that just because a dog has a white coat doesn't mean it's a double merle.



Are White Great Danes Albino or Rare?  


Double Merle and Albinism are not the same. Albinism is a rare condition in all animals, including dogs. People frequently associate Double Merles (White Danes) with being albino when, in reality, being a Double Merle and suffering from albinism are completely different conditions. True albinism is a genetic condition in which the pigmentation of eyes, coat, and skin are 100% absent. And NO, there's no such thing as a "part albino" dog.

In Double Merles, the white coat is produced by a doubling up of the gene responsible for Merle. A light-colored background and irregular spots characterize their coat pattern. Merle makes melanin pigmentation less intense in random areas of the dog's body.

Unfortunately, DM Great Danes are more common than they should be. Most unethical "breeders" will tell you that the White Great Dane you are eyeing is a lightly marked harlequin or simply just a harlequin. They often deny the dog is deaf and/or blind as well. Most Backyard Breeders are either uneducated about breeding or in it for the money.


Are all White Great Danes Deaf and/or Blind? 


No, definitely not. They can be one or the other or even neither, though a healthy White Dane is more uncommon. With this in mind, deaf and/or blind are not the only risks of breeding spot x spot. The puppies in this litter can have a wide array of health issues as well as mental issues due to irresponsible breeding.


Here are some examples of health issues DMs can have:

  • Social instability and inadequacy: Dogs with sensory defects often cannot interact with their species or humans fully and satisfactorily. Many DMs fail to adapt to different situations due to a lack of social capabilities and have multiple problems coping with normal daily activities. Double Merles are often described as "shy" or "'spooky." With training, persistence, and patience, DMs will learn ways of adapting and adjusting to their environment.

  • Merle deafness: Develops in the first month of life; it is permanent and often debilitating to the proper social development of the dog.

  • Atopic dermatitis: Inherited allergies.

  • Skin cancer: Increased incidence reported in harlequins, white/lightly marked harlequins and merlequins puppies due to lack of protective pigment (melanin) from UV (sunray) exposure. Sunburns also occur often in dogs lacking pigment & this can lead to tumors/cancer.

  • Follicular dysplasia: A hair-coat problem of broken / dull hairs & "pimply" infection with a high incidence in white coated (& other dilute colored) dogs.

  • Multiple congenital defects: Double Merles may have a variety of organ defects which arise only as they grow or may be seen when they’re young, such as failure to thrive & keep up with the size, weight and activity level of the other pups.

  • Congenital cataracts: Associated with microphthalmia - a blinding disorder.

  • Microphthalmia: Small eyeballs that often lead to total blindness. Sometimes the eyeball(s) must be removed.



Can Solid Colored Danes have Double Merles?


The answer is YES! We have rescued more than one DM from a spot x solid and solid x solid breeding in the past. Solid-colored Danes can be Cryptic Merles.


Cryptic merles are dogs that show only very slight merle coloration, and in some cases, it is not visible at all. Even though the Merle gene is dominant and can be seen most of the time, genetic testing both dogs before breeding is important to ensure they do not carry Merle, and therefore, there's not a 25% chance of having double Merles. It all comes down to responsible dog ownership and preventing the 25% of happening. Don’t forget: DMs are 100% preventable!


Are White Great Danes Adoptable? 


Yes! While not every special needs Great Dane is adoptable because of some of the issues mentioned above, most are. They can be wonderful additions to the right families and extremely rewarding to own. Training is not impossible but requires time, patience, and consistency.


Some of the Dog Breeds that Carry the Merle Gene Include:​


  • American Cocker Spaniels

  • American Pit Bull Terriers

  • American Staffordshire Terriers

  • Australian Shepherds

  • Beauceron

  • Bergers des Pyrenees

  • Border Collies

  • Cardigan Welsh Corgis

  • Catahoula Leopard Dogs

  • Chihuahuas

  • Collies

  • Dachshunds

  • German Collies

  • Great Danes

  • Hungarian Mudi

  • Mixes/Designer Breeds

  • Norwegian Hounds

  • Old English Sheepdogs

  • Pomeranians

  • Shetland Sheepdogs

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