#mismark

GirgLmoo by Alexaphyr

I WILL TAKE POINTLESS BREED INFORMATION FOR ALL BREEDS

Here, have some random Labrador things! Forgive me while I nerd out.

A favorite topic of mine: mismarks! Labs, of course, generally are seen in one of three colors: black, chocolate, and yellow. The color inheritance is fairly simple (and honestly Ebon’s yellow+chocolate=black thing is what sparked my ridiculous fascination with canine color genetics). The simpleness, imho, makes is a good introduction to genetics (and, in fact, is used on this site which is a pretty awesome resource on the subject, despite me cringing at the lack of independent assortment in that dihybrid cross). In Ebon’s case his parents were most likely BBee yellow (dad - yellow not carrying chocolate) and bbEE chocolate (mom - chocolate not carrying yellow). The pairing would thus only be able to produce BbEe puppies (black, carrying chocolate and yellow) which would explain why Ebon’s litter was all black.

BUT! I’m getting sidetracked. Mismarks! Labs, like so many breeds, have some non-standard colors that can pop up on occasion. Ignoring silver (*sigh*), residual white is probably the most common mismark/non-standard variation you’ll come across. Lab standards generally won’t DQ small spots on the chest (and Bolo spots are generally considered a non-issue), but Labs can pop up with white toes and/or pretty sizable patches on the chest. Tan points and brindle points are significantly rarer, but do occasionally pop up in the breed (you can see some rather striking examples here, here, and here). All three of the standard breed colors are based off of dominant black (chocolate/liver is basically just modified/lightened black, and yellow/recessive red ‘hides’ the black) and in the case of tan or brindle points, both parents would have to have one allele that’s, well, not dominant black. This allows what’s hiding below to peek through (tan point is on the A/agouti locus, along with sable, and since as far as I know there hasn’t been a confirmed purebred sable or agouti Labs it’s likely the breed is fixed for the tan point gene underneath the black).

Ebon himself is some sort of weird mismark (most likely a heavily striped black and brindle), and I blame him again for my fascination (I love this dang dog too much, lmao). I didn’t even know pointed Labs were a thing until I was sitting with his feet in my lap one day, went “why is his leg rusty???” and then started hunting.

There’s also funny things like chimera/mosaic and vitiligo, but those are entirely different kettles of fish.

I feel like Labs are a weird breed entirely due to their popularity (and my interest in their weirdness is almost entirely due to me having a weird AF one land in my lap). There’s just so many that you see things you just probably wouldn’t come across in a less common breed. Beyond just the huge variety in appearance, there’s also a lot of variation is what different lines carry. And it’s more than just health problems (while some lines are highly prone to problems, like epilepsy, that are absent in others). My favorite “well, that’s odd” is a case of dwarfism. Of course, Labs aren’t the only breed that can exhibit dwarfism. Excluding breeds that are dwarfs by design such as corgis, dwarfism has popped up in GSDs, Malamutes, and a search on Google Scholar shows cases in many, many more breeds. However, most of those are detrimental to the dog’s quality of life due to such things as malformed legs or pleiotropic effects. In at least one form of dwarfism seen in Labs, the dogs have few negative consequences.

I’m speaking about one particular Lab line that was the subject of this study. I also think this is a great example of how certain breeding practices can cause a recessive health problem to proliferate, since every single affected dog in the study is related to a single male that is the possible source of this particular form of dwarfism. Popular sire syndrome in action.

Lucky for you I know a lot of random shit! 

I’ll do some more Labby things later, but for now how about cream basenjis?

There are some more historical photos here and here. 

The color is extinct now, as far as I know. However, early on in the breeding of basenjis outside of Africa they were a pretty common sight. 

Cream Basenjis arrived out of the blue in the first litter to be born in England…then occurred occasionally, but were carefully bred out so that most people in the breed have no idea of what a cream looks like…

- Veronica Tudor-Williams, “Observations on Hemolytic Anemia” - 1972 

And they weren’t just light red, either. 

…pink nose, pink lips, and pig-like pink eye-rims. The eyes were a very curious green-yellow. In fact it was very reminiscent of the albino kangaroo In the London Zoo at that time

- Veronica Tudor-Williams, “Letter on Cream Basenjis” - 1979

It sounds an awful lot like cream basenjis were actually expressing incomplete albinism, much like the ‘white’ Dobermans of today (which are really cream with white points and frequently have pale greenish eyes).

(Sidebar: that photo’s from a study on albinism-related health problems in white Dobes, which you can read here: A Partial Gene Deletion of SLC45A2 Causes Oculocutaneous Albinism in Doberman Pinscher Dogs)

Through the AKC, cream and white is still technically a registerable color in the basenji breed. However, the only modern dog I’ve come across that has been registered as cream definitely has normal skin pigment (though diluted; Avongara Siri of Brushy Run indeed was only registered as cream because basenjis currently cannot be registered as blue fawn). 

Ebon’s rusting :-)