Wow, I just finished reading this entire thread. Jeanie, I totally understand where you are coming from and believe you wholeheartedly that you did the appropriate research to determine that your Chachi is not a mutt.
I think this largest problem here is that people do not even begin to understand complex genetics. A dog with a recessive/recessive color trait (we'll call is "rr") bred to a "rr" will ALWAYS produce "rr" puppies - there is no recessive to a recessive, and there is no dominant to override the recessive trait - therefore you're left with only a recessive trait that will show.
Next, after taking several evolutionary biology courses, I have studied and learned that all dogs originated from the Wolf. So thousands of years ago, there were not hundreds of breeds of dogs - that said, all breeds emerged at a different point in time. It's not like evolution is a new thing. Just because parti's have recently appeared doesn't mean they're a yorkie/maltese mix. Those of you that argued that the white coloring of the partis came from a mix - will you also argue that the rare albino dog mated with a polar bear? NO. I mean come on, the abino trait is also a recessive trait that doesn't always show. BUT, if you bread an albino to an albino, you'll get an albino. So, if you find a parti puppy in a litter and breed it with another parti, you'll get more parti's. Everything has to start somewhere.
Continued on the next post.....