Sonrisas Havanese ..."Autoimmune problems seem to be the biggest health issue in the Havanese, which is perfectly understandable considering that there were so few dogs used to rebuild the breed. Lack of genetic diversity increases the chance of autoimmune problems in any mammal and especially in dogs. "
I agree that autoimmune problems are a big problem in the breed... possibly the biggest, though crooked fronts and bad patellas a re right up there too. (and autoimmune problems are on the rise in all breeds and mixed breeds, which means there is something other than JUST genetics involved) However, the UC Davis study is not showing that we have an excessively small gene pool... probably because our "foundation stock" was not all purebreds. Dorothy Goodale collected them based on phenotype, not with any for-sure pedigrees on a number of the dogs. Plus the addition of some eastern European blood that was probably not purebred, infant it is strongly suspected that some weren't Havanese at all. ...Add to that that the Havanese being added to the gene pool from Cuba are, genetically, not closely related to the "American Havanese at all, and as long as people are careful, we have a lot of genetic material to work with.
What the UC Davis study is showing, however, is that we ALSO can't tell for sure how closely related two dogs are in terms of their genetics, based on how closely related they are by pedigree. Two full siblings can have remarkably different genetics due to the genetic "roll of the dice" inherited from each parent, while two dogs who would appear, based on pedigree, to be a pretty good outcross, could have more genes in common than you would expect. The information coming out of UC Davis shouldn't be used as the ONLY way to determine whether a certain breeding makes sense, but it is certainly a useful data point to help breeders make sound decisions.