Треба да се обрне внимание на текстот во статијата. Споредбата кучиња со останати животни. Зошто е толку голема разликата.
If one popular dog produces many offspring, lots of copies of its genes, both good and bad, are introduced into the population. As the number of copies of the lurking recessive alleles increases in the population, the chances grow that two dogs will get paired up that both have a particular recessive allele, and that's when you start seeing affected - homozygous - puppies. The size of the population can be important here - in a breed with tens of thousands of dogs (think Labrador or Golden Retriever), there have to be many more copies of the bad allele produced (in the form of puppies) than if the entire breeding population is just a few hundred dogs (think rare breeds like the Chinook or Icelandic Sheepdog). Small breeds are much more vulnerable to the accumulation of recessive alleles, and there is a much higher risk of the allele becoming "fixed" in the breed (i.e., all individuals are homozygous for the bad allele).
The other way to end up with affected puppies, even if the frequency of the recessive allele in the population is very low, is by breeding closely related dogs. A sire carrying a bad allele that is bred to a granddaughter stands a good chance of producing homozygous pups - and both copies of the bad allele could actually came from him. (This is called (homozygous by descent", meaning both copies of the allele were inherited from the same ancestor.)
So back to the graph above. Most genetic diseases in dogs are a consequence of paired autosomal recessive alleles, and this has occurred because of the breeding practices we just discussed. This means that
these diseases were entirely AVOIDABLE. It's no mystery why the list of inherited disorders continues to get longer, and if you think you are in a "relatively healthy" breed think again. There are bad alleles in ALL dogs. You have no way to know which are in your dogs, or even your breed, until they are expressed.
http://www.instituteofcaninebiology.org/blog/do-dogs-have-more-than-their-fair-share-of-inherited-disease