|Image is from Flickr.com under a Creative Commons license|
This is Tink, a Doberman pinscher. Thanks to the lighting, it's difficult to differentiate her tan points, but they're definitely there. I could also see people confusing her for a Weimaraner due to her color and natural ears, however this coloration is very possible in the breed, though some countries don't allow it in their standard. This is mainly due to the high incidence of blue dilution alopecia that is seen in the breed, and I'll get back to how this is relevant to Tink. Anyway, on to her genotype.
First, Tink is tan pointed/black and tan, as all Dobermans are. The gene is fixed in the breed, and all color variation is caused by the action of other genes. Since this is true, Tink has to be atat tan pointed.
Next, she is also liver, known as "red" in the breed. The gene is recessive and results in the black in the coat becoming a brown color. She is also blue, another recessive gene that results in the black in the coat diluting down to a gray color. The two genes combined are what causes her coat to be the sort of putty-like color that is known as Isabella or fawn in the breed. To be fawn, a dog must be bb dd fawn (liver + blue).
The red that is seen in this dog's coat is also very dark, as with nearly all Dobermans. Going with the theory that the Chinchilla locus controls red intensity, this would make her CC dark red.
So, that's atat bb DD dd or fawn with dark red points.
Back to BDA: since fawn dogs are genetically blue, this puts them at risk for blue dilution alopecia just like blue dogs. In Dobermans, up to nine in every ten blues have it, and about three in every four fawns do as well. Does Tink have this condition? It's difficult to tell since her coat is very similar in color to her skin. However, it's quite possible that she does. Some pictures of her point toward yes, which isn't surprising considering how prevalent the issue is in the breed. As I mentioned previously, some standards don't even allow blue and fawn, and the main reason for their exclusion is likely due to one disqualification being a "pronounced thin coat or large bald patches," both of which are very likely in the colors thanks to blue dilution alopecia.