Re: [pyrnet] Black Pyrenees, White Newf...

["Jessica @ DaVor" <woods@davor.com>]

on 7/8/02 17:15, Chrissy McConnell at chrissy_mcconnell@hotmail.com wrote:

> Now, can anyone who has studied color genetics a little more than I,
> especially in cats, explain the seemingly dominate white with the gray spot
> and no deafness as is often the case with white cats and often blue eyes?
> 
> Chrissy  :)


In cats, as I understand from university bio classes, the genes for hearing
and coat/eye pigmentation are on the same chromosome.  And in the cases of a
PURE WHITE (no other pigmentation anywhere) cat with blue eyes expressed,
the deafness also expresses.  In cats, white coat, blue eyes, and deafness
are all recessive genes.

Remember that eye color especially takes multiple genes--up to 8 separate
genes in humans, as I recall.  So in order for a cat to have truly blue
eyes, several pairs of genes must be recessive.  But that makes for a large
group of recessive genes when it is present.  In the case of cats, this
recessive triple whammy (coat, eyes, ears) must be a VERY old set of genes.
But because the heterozygous or "mixed gene" cat doesn't express those
recessive genes, only carries them, it's a combo that can't really be bred
away.

Another theory that I have heard is that the expression of blue eyes codes
for a protein that prevents the expression of functional hearing.. but I
think that's less likely.

Jess & Sam
Levittown PA
woods@davor.com