Oh, I knew you weren't talking about the parti gene and no, I'm not trying to go there
I just used that as an example most could relate to. Genetics does all go back to Mendel, but animals are much more complex. I'm still trying to wrap my head around it.
Going back to the Yorkie coat, 3 distinguishing characteristics (long, straight and smooth) are recessive traits. Sounds easy to lock all that in but it's entirely possible to get a wiry coat, for example, from silk coat parents.
The list I've seen of recessive and dominate traits is the same as what's posted in this thread. In the book I have that's just what it's called... recessive and dominate traits. It doesn't specify if they're single gene characteristics or not. I would think not all are since coat predictability isn't 100%.