A parti yorkie's coloring is the result of a recessive pie bald gene. It is possible for two standard colored parents to carry the gene and isn't apparent until those two dogs produce a parti colored puppy. If someone breeds a parti to a parti...the resulting litter will be all partis. The dogs don't have any other gene to offer...if a dog is a carrier and breed to a parti..it is possible for the resulting litter to contain both standard and parti colored puppies.
Pinehaven is a parti breeder here. Send her a pm...I'm sure she'd love to talk "parti".
