Aussie Genetics Fact Sheet
by C.A. Sharp
Cryptic merles, sometimes referred to as “phantom,” are dogs which carry a particular version merle gene, sometimes two copies and sometimes one with a copy of the version that results in no merle pattern. At a glance they appear to be tricolor or bicolor dogs. Cryptic merle Aussies will be either liver or black. Most of these dogs will have some small area of merleing somewhere. One of the most famous in this breed, Fieldmaster of Flintridge, looked like a black tri except for one or two very small merle areas.
When the merle gene was identified the researchers also discovered that a particular version of this gene causes cryptic merles. Unlike regular merles, these dogs apparently do not produce the eye and hearing problems seen when a puppy inherits two copies of the regular merle version of the gene. Dogs with two cryptic versions or one cryptic and one normal version will be sound. When bred to non-merle dogs, all the puppies will be either non-merle or cryptic. Because Aussies have white markings, it is probable that some dogs who have the cryptic version of the merle gene will not show any merle spots because the place they would have been is obscured by a white marking.
For show breeders, registering cryptic merles is a problem for a breeder. They are a form of merle, but will appear more like non-merles. They are not incorrect in color but if shown in the Open classes, which are traditionally divided by coat color, they will look very wrong in the merle classes and may cause the judge to question their presence in the black or liver (red) classes. There is no option for registering dogs as cryptic merles.
Excessive white markings in puppies from a tri-to-merle cross or white markings mottled by ticking spots are not an indication that the apparently non-merle parent is a cryptic merle. Excessive white markings in such a cross are the result of genes which code for white trim and have nothing to do with merle.