Guess the Genotype #75

Can you guess this dog's genotype? Its breed?

Image is from Flickr.com under a Creative Commons license

This dog is a Newfoundland of the Landseer variety. Though most people think of a solid black dog when they think of a Newfoundland, Newfies come in many more colors. These include brown, gray, and the white-marked Landseer. So what are the genes that go into making a Landseer?

To begin, this dog is genetically solid black. There are two forms of black known in the dog world: dominant and recessive. Newfies have tested positive for the dominant black gene, and the breed as a whole appears to be fixed for the gene. This would make this pup KK dominant black. All of the Newfie colors are built around this single gene, with recessive genes acting on the black to produce the other acceptable coat colors.

What turns a black Newfie into a Landseer? The Spotting locus is responsible for the white seen on dogs. A black dog would be genetically solid (S), while a dog with prominent white markings would be either Irish white (si), piebald (sp), or extreme white (sw). It appears that extreme white isn't really present in the breed, and that Landseers have some combination of Irish or piebald alleles. Though this puppy appears to be almost completely white, this is far from the case. It has quite substantial markings down its back. I suspect that this pup is a rather heavily marked spsp piebald.

Lastly, there are also ticking spots on the dog's legs and face. For this to be present, a dog has to have at least one copy of the ticking gene. Since this dog is only a puppy, it's likely that it will end up with more spots than it already has. Since quite a large number of Landseers have ticking, I suspect this dog is TT ticked.

So, that's KK spsp TT or black piebald with ticking.