This dog has the black spot phenomenon on his face.
The black spot phenomenon happens in golden and yellow Labrador retrievers when dog experiences a somatic mutation that turns the e/e to E/e. e/e is the genotype that produces the yellow to red coat color in golden retrievers and yellow Labs. If they had the E/e or E/e genotype, they would either be black dogs or liver/chocolate dogs.
It’s not a really a birthmark. It’s just a somatic mutation.
Here is the same dog as an adult. He is standing beside his mother, who doesn’t have that somatic mutation. Because this is a mutation in the somatic cells, it is not passed on from generation to generation. Breeding a dog with these spots to another dog will not produce spotted puppies.
You know that and I know that but try tell that to the front office.
this is a great example of what might be called “midline effect”– the mutation took place in a cell on the left side of the body, and the cells developing from that original cell (and capable of producing black hair) are all on the left side, although they’ve been spread in an irregular pattern. There’s a photo in “The New Golden Retriever” book showing a Golden with several patches of black on one side, with absolutely no black on the other. The same effect can sometimes be seen in merles, where some patches stop abruptly at the midline.
That’s the book where I first read about it : )
http://al-sarab.webs.com/Mamnouna/Cheschmesch4.JPG
One of the coolest-looking dogs, that one.
I had been wondering if you’d ever seen this dog. I found him on flickr ages ago. It had to have been such a shock when he came out of the womb!
If this same thing happened to a brown-skinned yellow, the spots would be liver.
I have looked everywhere for a photo of a brown-skinned yellow with this mutation, but no luck.
I have also looked for this, but so far I’ve not found one. Somatic mutations like this one pictured also happen in ranched foxes and in at least one African lion. The fox I saw was a standard blue fox with a patch of black which ended on the dorsal midline. It looked like an oddly done taxidermy job.
Do you know who owns this Golden?
If you click on the “Source for the image” link, it will take you to this photostream:
http://www.flickr.com/photos/sally_mcburney/
If you go to http://isleofcolegoldendoodles.com/females and scroll all the way down they have a female goldedoodle who is a browned-skinned yellow
There are a couple of brown mosaics here: http://www.woodhavenlabs.com/mismarks.html
Ah,. The Labrador people call them “mosaics.”
We call it the black spot phenomenon, because it’s not really an inherited color. It is a somatic mutation and can strike any puppy born to any line.
My recollection is that mosaics are somewhat different from the ‘ordinary’ random black spot– that a true genetic mosaic is due to a happening much earlier in the development of the embryo(s), and that the different parts making up the mosaic can be more different genetically than just hair color. Rather as if what started out to be fraternal twins blended into one entity. I recall a program on one of the TV channels a few years ago, featuring a woman whose ovaries and ova were of quite different DNA than her blood; this was discovered when she was tested for compatibility with her daughter who needed a transfusion or a transplant (don’t remember those details) and it was found that by blood testing she couldn’t be her daughter’s mother, but testing of other tissues showed that she was!
(Perhaps one of you internet explorers can find the relevant references)
Well, mosaicism would be an appropriate term for it. A mosaic is an individual that displays two different genotypes which arose from a somatic mutation. Or in the case of tortoiseshell cats (where red and black genes are on the X’s), normal random inactivity of an X chromosome, producing Barr bodies and patchy color.
One question with the Labradors is actually about the potential the “mosaic” dogs could in fact be chimeras. In chimeras, the different genotypes come from the fusing of two embryos. Genetic testing would have to be done to determine that, however, and chimeras are really not that common.
The golden would have to be a mosaic.
http://www.vivo.colostate.edu/hbooks/genetics/medgen/chromo/mosaics.html
Steph, thanks so much for the clarification! The example of the woman I mentioned was indeed of a chimera rather than mosaicism. blame it on my less-than-perfect recall….
Here’s one of the most informative & interesting articles on chimeric animals that I’ve seen. Read promptly, because the links keep changing…
\http://instructor.mstc.edu/instructor/MKundinger/oneinamillion.pdf
I recall a woman who was trying to breed brindle horses had some lack of success because, in fact, her brindle stallion was a chimera–with the brindle pattern actually being an effect of two different sets of genes for different coat colors.
re: black mismarks–I remember seeing a black and red import German Shepherd with a black patch on one hock–it was about the size of my palm–didn’t know what it was at the time, but I suspect it must have been a somatic mutation.
Very dramatic Lab here:
http://greenstonelabradors.com/understanding-mismarks-in-the-purebred-labrador/
Oddly, that website has this yellow-with-black dog positioned between “brindle” and “white markings” — neither of which is appropriate.
The ‘woodhaven’ website appears to attribute both tan markings and brindle markings to a Gordon Setter outcross — however, early writings and illustrations show the bicolor pattern mrkings of both colors as being well-known in the ancestry of the Labrador Retriever. The brindle is often referred to as ‘tabby’ markings.
I have a pup here for training that has black markings underneath his left ear. When the owner contacted the breeder to tell her that the pup had black hairs, the breeder denied it by telling the woman that the pup had rolled in black wood mulch when he was wet. Uh, yeah…
The dog is now a year old and the woman INSISTS that the marking is a stain.
He’s a clever little guy, much more clever than his owner to be going out and re-rolling in some mysterious black mulch every time he has a bath or a trim…
i want one of these dogs. they are sooo cool looking!
I believe you are right completely…
what’s its name?
“Peter Fox.”
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My dog had 1 puppy from her litter with a black spot right behind his left ear. For a few days, everyone (even the vets) insisted that it was just the print from the newspaper transferring onto his fur. But as soon as I saw him, I googled “black spot on golden retriever” and was directed here. Thanks! I know the vets probably don’t know about this phenomenon, but I wish they did! Even the breeder claims that our dog probably isn’t even PURE golden! Crazy.
Needless to say, the puppy is perfectly well. He also has a small kink at the very tip of his tail.
Just brought home the most GORGEOUS 12 week old Golden Retriever. She has what looks like very light smudges in 3 or 4 spots on her back. Looks like someone petted her with car oil on their hands :) breeder seems to think that because her skin under the spots is normal colored that she may lose the spots as she grows. I really don’t care -just fell in love with her. Ended up here when I googled it out curiosity. Definitely not as pronounced as the dog pictured but I’m assuming it’s the same phenomenon responsible. Thx for the info.
Sometimes the black hairs are not wholly black, but rather are sable: that is,black tips on yellow hairs. Some Goldens do carry the gene for sable, but because the e/e ordinaril prevents expression of. The black pigment, it isn’t evident. Unless in an area affected by the somatic mutation (which allows black pigment). Black-tipped hairs could easily give that impression of a “smudged” area.