Let me try again.... The two main divisions in dog hair is the differentiation between the double-coated "FUR" and the single'coated "HAIR" -- Yorkies come under HAIR of course.
The examples Pinehaven was using are the genetic ideas behind the different coat-types. For example there are wire-haired dogs, long hair dogs, curly haired dogs, short haired dogs, and then some combos -- wire/curly, long with furnishings, curly with furnishings. Our dogs come in to the long hair dogs category for this genetic concept. Has nothing to do with the wave in some yorkies hair -- they are all long haired dogs for this concept.
Here is another site that explains Hair Curl (DNA marker tested – KRT71) The presence of "Curl" is inherited as an
autosomal Dominant trait. Therefore, dogs having only 1 copy of the curl allele will appear to have a curly coat, but will likely pass on the non-curl allele 50% of the time.
Canine Coat Length Test for German Shepherd Dogs, Rottweiler, and Cardigan Welsh Corgis
I think that one other site with the Rr listed has just been copied on site after site, without proper explanation as how it would relate to dog breeds specifically.