Re: [pyrnet] Consider breeding carriers (a proposal)

["Linda Weisser" <lmweisser@olywa.net>]

<JGentzel@aol.com>

<<the diversity of mutations that occur as far a degrees
of involvement and the whether there is deformity or degrees of deformity.
 <snip> Could a simple recessive problem 'sometimes' be accompanied by a
poly genetic problem that would account for such observations?>>

Most correctly these are not "mutations" but simply variations that occur
within a condition.  These are found in almost all things.  I think that
simple "normal" variation could account for most of the differences we see
in dwarfs and we do not have to look to accompanying poly genic
explanations.  For example PRA is a simple recessive in all breeds except
Siberians.  However, PRA manefests itself differently in different breeds.
Early onset, late onset.  Rapid development, slow development.  Even within
one breed these things can vary.

<<Also some of the less obvious dwarfs are just said to not be
dwarfs even though it is probable that they are.>>

Yes, it is probable for some at least.  At this point we (as in the
committee, the fancy) have only followed one such dog closely.  His
radiographs at 8 weeks and at 7 months were evaluated by Dr Sande who said
that the osseous changes are characteristic of chondroplasia.  This is one
of those dogs that falls within Joe's concerns above.  he exhibits great
variation from what we normally think of as a "dwarf".  Dr Sande's
observation was (to paraphrase) that we did not know the range of variation
that could accompany this condition in Pyrs.

As for "less obvious dwarfs" I think that we have to exercise great caution
in these situations and assumptions.  We have some *very* small individuals
in this breed that are not dwarfs.  Simply being small does not make a dog
a dwarf as I know Joe knows.  If we are going to talk about these less
obvious dogs as dwarfs, we can only do so with authority if we have the
sort of radiographs that have been done on the dog above.  Anything else is
speculation.  Technically no Pyr can authoritatively be called a dwarf
unless there is radiographic confirmation, although with the really small
statured ones, we do it all the time.

Linda Weisser
lmweisser@olywa.net