Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

Generic selectors
Exact matches only
Search in title
Search in content



Are black or red non-merle dogs that have irregular white spots on the ears or body actually cryptic merles? 

If the hair is white, no.  The small merle spots seen in cryptic merles will be colored blue or light red.   If there is doubt, examine the hair under a microscope; pigmented hair will have visible pigment in the hair shaft. No visible pigment means the hair is white and the dog just has white spots.

Are black or red dogs that have puppies with too much white cryptic merles?

No.  Having two copies of  Mcr does not produce an obvious merle pattern, nor excess white.  The excess white would have been caused by another factor, such as a recessive piebald gene.

If a cryptic merle is bred to a regular merle, will there be eye and ear problems?

It depends. Because the SINE insertion is unstable and can combine to become longer or lose some of its length to become shorter, there is no absolute answer here. If the cryptic copy were to gain length to the point that it became a regular merle gene in the puppy then defects associated with a double merle might occur.  Frequency for lengthening is low, probably around 3%.  The frequency for losing length is much higher. In most cases it is safe to breed a cryptic merle to a merle and not produce defects nor excessive white associated with an (MM) individual. (M Mcr) would look like a normal classic merle.