Re: [pyrnet] Pyr eyes

[darrell goolsbee <dgg@star-telegram.com>]

<<Cataracts has the real problem of "carriers".
>  That's
> the major danger to the breed.  In some cases the Dx tells you what
> dogs
> (both parents) are carriers and then the real problems begin.  How
> many pups
> are already on the ground (50%) will  be carriers or have the
> condition,
> roughtly.>>

All breeders will have to weigh the risks for themselves. But let me
quote this advice from Dr. Gustavo Aguirre, head of PRA research at the
Baker Institute of Cornell University. I think it is likely good advice
not only for PRA, but for any serious autosomal recessive.

Aguirre and other genetic experts advise against using any affected dog,
any known carrier, or any dog with a 25 percent or greater probability
of being a carrier in any breeding program. This is done in order to
limit the spread of the defective gene, and to reduce the chance of
inadvertently breeding a carrier to another carrier. Offspring of an
affected parent are ALWAYS (emphasis mine) carriers or affected,
depending on the other parent. Offspring of a known carrier have a 50
percent probability of being carriers if the other parent is genetically
normal. Grandchildren of a known carrier have a 25 percent probability
of being carriers. 

Darrell Goolsbee
Fort Worth, TX