Show me your Melanistic Blanket GSD - Page 9

What the hell is that little weak-eared panda doing in the foreground?  

I know I've said this many times on this forum... and I've tried to keep out of this thread BUT -

Bicolour/melanistic/saddle/B&T  these are all expressions of the same allele on the A locus.  IOW  all the same 'gene'

The a^t (tanpoint/ B&T) allele has a wide phenotype from the palest saddle to the darkest bicolour and this runs in a pattern of continuous variation contolled by separate gene/s. So, bicolour can be whatever you want it to be.

This has been generally accepted in the colour inheritance community for some years now, and finally, as the DNA research on the A locus is completing, it will soon be published.

Now why the heck did you stay out of it????? You could have saved me two days of making little boxes and peering at tiny pictures of dogs trying to figure out colors!!! 

What pod's describing is very on par with what I was trying to explain in PM.  Is this the thread you mentioned?

Yes! And I totally get it now! I also totally get WHY my sable girls are black on the underside...because they are tightly linebred. Is that correct?

I was right then. IF bicolor was an actual separate gene, I would NOT have been able to get three bi-colors in my litter. No way. It just proves that b&t is all the same gene but in varying degrees. It's meaningless except as a general sort of description. 

I would like a grade for that test, please.

If bi-color is the same as black/tan, then why do bi's bred to bi's NEVER produce blk/tan?

Okay, obviously I have not seen every litter bred but I have never seen or heard of a bi/bi mating, or a bi/black mating, produce anything other than bi and black.

Everytime I have seen a breeding that claimed discrepancy, the colors were mis-stated.

--Mary

I'm going to take a wild guess and say that since bi is in the melanistic category of German and Czech registering, the answer lies in the melanin. If you breed two dark dogs with lots of melanin, it would probably be unlikely that you would get a lighter dog. But that is a wild guess! The deal is that the DEGREE of color in a b&t is an additional gene, almost like a masking gene. In the other registries, the available colors for registering are:
light sable
dark sable
black and tan
melanistic black and tan
black

That is actually a total of 3 available patterns/colors with differing degrees. But some people argue that there is only ONE pattern--sable--and everything else is a sort of "failure to be sable" brought on by mutated genes. Add that to melanistic gene, and you have the variations. Anyway, that's how my little non scientific head processed it.

I think black and tan markings/variations are all one color and melanin is an additional factor that influences color. It'd be like...you have to have two dilute factors to get a dilute puppy. If you have two dark factors, you get dark puppies.

I hope Daryl or pod comes back on this one! I still don't know if I even passed the test! 

I would give you a mark of Melanistic B+

Ibrahim

With this understanding that B&T, bicolour etc is all one 'gene,' this doesn't negate the long held belief that 'more tan' is dominant to 'less tan.' ie. saddle is dominant to bicolour. 

The probable explanation is that one or more genes with multiple alleles controls the balance between dark and light pigment, possibly with some co-dominance, which could then in some circumstances produce lighter offspring from dark parents, and vice versa.

One gene that could be implicated here is the mask gene.  Dogs with particularly heavy facial mask also tend to have heavy dark shading, most obvious in sables, but this could also be responsible for dark overlay in B&Ts, often seen down the legs - tarheels, pencil marks etc.

Just read your excellent post VM.  Thinking along the right lines I'd say :)