Panda Shepherd - Page 3

Hi Inca.  The possible explanations for this that spring to mind -

1)  This is the product of a rare recessive carried in the breed, possibly 'irish spotting' on the S locus that is responsible for white spotting in many breeds eg the Collies.  Or a recessive from a different gene producing a similar pattern to S locus.  I believe DNA researchers are working on this at the moment and the liklihood is that there is more than one gene responsible for the usual white spotting.

2) A new dominant mutation has occured that is peculiar to this pup as was the case in the Panda Shepherds.  It could be the same gene as the Panda or a completely new and original mutation.

3)  It could be the product of a developmental blip and not actually under genetic control.  The placement of pigment in a developing embryo in vitro is controlled by multiple genes but the melanocyte migration is still somewhat random so it could be that something has interfered with the migration pathway to cause the pigment to be missing in certain areas of the body. 
Evidence of this patial random nature of melanocyte migration can be seen when cloning of some species has been carried out.  Horses, cattle and cats have all shown variations in the white markings amongst clones and this is why breeding for very specific white markings, as is the practice in many breeds, is much of a hit & miss practice.  This  phenomenon is know as 'developmental noise' is you want to read further.

4) Sorry got to include this forth one although I'm sure you wouldn't be wrting here if you thought it possible :-)  The possibility of a big white dog having jumped your fence!

Incavale, would you be willing to post a picture of your pup?  This is very interesting stuff...

Heather

Photo taken when the pup was 24 hours old

Same pup. She is one of 5 in the litter. The others are black/gold.

wow, very interesting.

From the photos I'd say #  1) and 4) are more likely than 2) and 3), not ruling them out though.  A simple DNA parentage test will rule out 4).

What usually happens with S locus spotting is that the white markings decrease in size as pigment cell migration continues after birth for a few weeks, often much longer in some breeds and most noticable on the head, neck and tail tip.  If this is S locus then this pup will probably end up with a much narrower blaze.  This pup's marking do look very much like the S s^w genotype of the flashily marked show Boxer.

Do you have photos of this pup with the rest of the litter?

Not at the moment but will take some & post them

We can rule out any stray dog getting to the bitch. She was absolutely secure.

I think we are seeing these off colors or markings popping up with such frequency nowadays due to the amount of linebreeding that has went on with our breed.   we all have seen the pictures of dogs who were our breeds foundation, many had these white markings.  I feel these puppies are just throw backs to those original dogs.  has anyone checked the inbreeding coeffiecent on litters were this marking has came up in?  I would be curious to see what dogs appeared predominantly in the pedigree many generations back.

I have seen other litters with this coloration, some of them have a white parent, other litters have came out of very rick, dark colored dogs with no white ancestors or white spotting.  Both american and german lines have produced this.