Wednesday, January 18, 2012

Guess the Genotype #45

Can you guess this dog's genotype? Its breed should be easy.

Image is from Flickr.com under a Creative Commons license.



This is Rio, a domino Afghan hound. Now, what does the domino coloration mean, genotype-wise? It's more complicated then to dog simply having a copy of the domino gene.

To begin with, Rio must be tan pointed. Though it doesn't seem like this is very likely, in fact it is the case. For a dog to express the domino gene, it must be genetically tan pointed. The domino/grizzle gene then acts as a modifier on the tan point, creating the classic appearance of grizzle/domino, widow's peak and all. As such, Rio must be atat tan pointed.

As for the intensity of red on his dog, it is in fact quite pale. I suspect that Rio is cece very pale red (cream).

Next, is the domino or grizzle gene. For a dog to be grizzle, it only needs to have a single copy of the grizzle gene. Afghan hounds are known to have all of the different possible alleles of the Extension locus in the gene pool. As such, except for knowing that Rio has a copy of the grizzle gene, it is impossible to say whether or not this dog is homozygous for grizzle or carries the "normal" E gene or recessive red e. However, I am going to assume that Rio is Ege domino carrying recessive red.

Last, but not least, is the white spotting gene. Though it is difficult to tell because of the paleness of the red in this dog's coat, there are some white markings. They can be distinguished on the tip of the tail, on the nose, and the chest. There are also likely white markings on the legs and/or paws, however the fur is stained and has obscured any markings that may be there. Despite this, the markings that can be seen suggest a minimal Irish white marking appearance. Since white markings are undesirable in the breed, I find it unlikely that Rio is homozygous for the Irish gene. As such, I suspect that Rio is instead Ssi solid carrying Irish white.

So, that would be atat cece Ege Ssi or cream domino with minimal Irish white.

1 comment:

  1. I think it's the domino that makes his pheomelanin so pale and the whiter marks larger than what they would be if he was a regular tanpoint. Also I think there are such things as domino's with sable or wolf grey genotype "beneath" or even saddle back in some Nordic spitz type breeds (I know the same Eg-gene was not found in huskies, but it must be something similar).

    But I agree that Rio is a at/at, because his body is quite dark. A domino with a sable gene (and because hi is an afghan, a sable would be very bright) would not show much eumelanin at all.

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