Coat Color Genetics

I don't have a doctorate in genetics by any means but I do have a pretty good grasp and off the top of my head, I believe that the saddle back coloration is a single gene mutation as opposed to a double modifying allele. (saddle back is not the coloration that I I have studied)

It would help to know a little more background on the gyps lines and historic color traits but based simply on the information provided, it seems mathematically reasonable to expect a 10 to 15% chance of throwing at least one saddle back.

Of course genetics being the tricky thing that it is, mathematical probability can not tell you if that 10 to 15% chance will effect only one pup or all of them. Or none assuming that you don't hit that 10% lotto.

Id consider myself lucky if I got more than one saddle back from the breeding described, assuming thats what you want.

Steve