The Parti colored Yorkshire Terriers have only been recognized since the early 1980's. And have only been accepted by the AKC for about 3 years. Before that time they were either given away as pets, or perhaps even, in the earlier times, culled at birth. Parti colored yorkies are the result of breedng two traditional colored yorkies, who both happened to carry the parti color producing gene. One cannot tell by looking at a carrier that they are a carrier because most of them are traditionally colored and many are Champions.
The parti color producing gene is a recessive gene and it will not produce a parti colored offspring unless the gene is carried by both parents. However, the gene can be passed along from one parent to their offspring, completely unnoticed for many generations, only surfacing when a carrier is mated with another carrier.
Unusual traits such as this are more likely to surface in champion lines because it is not uncommon for show breeders to practice close breeding or inbreeding, of their champions, in an attempt to reproduce the desired traits found in the champion dog.
Just exactly when and where and how this parti gene became part of the Yorkshire Terrier makeup is unknown and the issue has become a great source of controversy. There is a great deal of speculation and if you research long enough you will no doubt uncover many different theories, but the truth is, they are all just theories. No one knows for sure and if someone does know, they're not telling.
The AKC DNA'd about 42 litters before they accepted our Parti-colors. The DNA proved they were 100% purebred Yorkshire Terriers. AKC does not require DNA on the dams but the same requirements for the DNA on traditional-color, breeding sires applies. Registering a Parti-color litter is exactly the same as registering a traditional litter. When registering an individual puppy from a Parti-color litter, the AKC requires four color photos (front, back and both sides) and the puppies are registered on a "case-by-case" basis.
The coat textures, temperaments, etc. are all the same as Traditional color Yorkies. These Parti-color Yorkies are simply AKC Yorkshire Terriers with alittle more Color!
Parti colored yorkies have been appearing for a long long time, but no one with a champion dog would ever want to own up to it for fear of being banned from the Yorkshire Terrier Club of America (YTCA)
There are Yorkshire Terrier breeders who will argue that the parti colored yorkies are not pure yorkies and should not be registered as pure bred dogs. However these same breeders could have a traditional colored carrier, perhaps even a champion, that came from the same litter as a parti colored and they would never know that it carried the parti gene. Is it any less a yorkie if it carries two parti genes instead of one parti gene and one traditional colored gene?