Ernest Hemingway’s grandfather had a white yorkie named Tassel in the early 1900′s and the book below (among other writings), talks of white yorkshire terriers.

A manual of toy dogs: how to breed, rear, and feed them By Mrs. Leslie Williams written in 1904.

“The white Yorkshires, a new variety some folk have tried to push, is, I think, in no way especially desirable—the Maltese can do all that is necessary in that line; while the attempt to make ” silver ” Yorkshires popular, too, simply means that bad-coloured dogs without any tan (paleness of tan is the stumblingblock in many a Yorkshire’s career), are classed by themselves and offered prizes.”

It’s the recessive genes of these early dogs, that are still being passed down generations later. Even though the dogs who began this breed may have been the correct color, it’s the recessive genes they carried that are producing other colors too. It takes two dogs who carry the recessive gene to be bred together before it will produce the off coloring.

The Kennel clubs have always been uber stuck up and silly about breed specifics. Doesn’t mean that the rest of us don’t adore them )