Sunday, August 14, 2011

Guess the Genotype #15

Pai from The Chinese Crested Shrine provided me with this image. Can you guess this dog's genotype? It's more simple than you may think. Can you also guess its breed?

From the file name on the image as provided to me, I believe this dog is a coated Xoloitzcuintli. This normally hairless breed comes in several sizes, and I believe this would most likely be the toy variety. All hairless breeds come in a coated version, the Xolo being no exception. As for color genotype, these are my conclusions: 

 To begin with, this dog is tan pointed. Though she lacks the normal facial markings, this is actually a not uncommon occurrence when other genes are in effect. The tan chest patches are also nearly non-existent, which is fairly unusual, but since the tan points on the legs are smaller than normal and sooty in appearance this is not unexpected (this phenotype is very common in Manchester Terriers). So, this dog must be atat tan pointed.

The other gene that is at work here, and which causes the loss of facial tan, is the masking gene. In cases where a dog has a very heavy mask, it is not uncommon for it to extend to cover most of the head. This is a common sight in the almost exclusively masked German Shepherds, which will often have a phenotype nearly identical to this dog. Though it is possible that this dog only has one copy of the mask gene, I don't believe this to be the case, which would make this dog EmEm masked.

As for the white on the dog, it is possible that that dog is Ssi solid carrying Irish markings, but I believe that she is instead SS solid with residual white.

So, that is atat EmEm SS or masked black and tan with residual white.


  1. Is it possible that the dog is at/a to account for the greater coverage of black?

  2. I suppose it could be possible as I am unfamiliar with the penetrance and expressivity of the genes on the agouti locus. However, I don't believe that is the case as this phenotype (not counting the mask) is seen in breeds such as the Manchester Terrier, which does not have the recessive black allele present in its gene pool.