Sana, pri parjenju merlov je možnost, da se mladički (eden ali več) rodijo z double merle genom, in so posledično ne samo popolnoma ali delno beli ampak tudi gluhi ali/in slepi in še kaj hujšega. Očitno nekateri vzreditelji še vedno upajo, da se bodo nekako po sreči rodili vsi zdravi ali pa jim pač ni mar in bolane pač uspavajo.
'If you breed DOUBLE merles, it means that you bred two blue or a blue and red together. When you do this you double the recessive merle gene and all the bad stuff rides on those genes, you can get a predominately white pup with very blue eyes, and this is where the blindness and deafness comes in.
Why "Lethal White"?
The problem with these double merle (or double dapple) dogs is that the genes that determine a dog's coloring also have a huge role in the development of his hearing and eyesight.
Lethal White in a dog is not actually deadly. It also rarely results in an entirely white dog; usually a double merle pup will have at least patches of merle somewhere on its body. But it can cause serious problems for the pups in its category, namely deafness or blindness, and even both! Pups born "lethal white" can also have malformed eyes or no eyes at all.'
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