Darrin writes
>As near as I have been able to ascertain ?  the genes for "most causes
>of deafness" are recessive, and only brought out in crossbreeding
>parents with the recessive gene, thus increasing the likelihood of the
>recessive becoming the only gene pair, and therefore dominant.
 
Actually Waardensburg is known to be dominant, and I believe others
such as KIT are too.  The problem is the variable expression of these
genes--it has the effect of hiding the defect in some individuals.
Another slight correction: having a pair of recessive genes does not
make it "dominant", it simply becomes expressed.
 
Darrin also writes
>However, my point was, ( and this is much easier with ferrets then some
>other animals, as they have a lot of kits per litter and statistics are
>easier per large litters).  If ANY of the subsequent kits are deaf..
>then NONE of the others from that litter should be bred as they are all
>now (or mostly) now obviously carriers.
    and
>As soon as there is any incidence of deafness, the entire bloodline
>should be shut down.
 
But your point is absolutely correct and well stated!
 
Linda Iroff
International Ferret Congress
http://www.ferretcongress.org
[Posted in FML issue 4670]