[PyrNet-L] RE: pyrnet-l-digest.19991220

[Jack Mowery <jack.mowery@asc.mhmr.state.tx.us>]

On 12/20/99 Robyn writes:

In a message dated 99-12-19 07:23:30 EST, you write:
<< If you line breed genetic 
problems you will identify the problems quicker and easier.  Linebreeding 
can 
and should be the messenger.  Lets not shoot it.  If abused or used 
inappropriately it could add to a problem, but that's true of anything.   >>
I will agree with you on this one, Joe.  Linebreeding, from my limited
knowledge of the subject, can be very useful in establishing and maintaining
desired characteristics.  I think where it goes wrong is when uneducated
"breeders" mistake inbreeding for linebreeding.  Then it can go horribly
wrong.
Robyn
dancingpyr@aol.com <mailto:dancingpyr@aol.com> 
Taylors, SC

I have to disagree with you on this one.  The problem is that line or
in-breeding either one are equally capable of reinforcing a bad
characteristic as a good one.  Random genetic drift (or mutation) is
originally responsible for any change from the normal, good or bad.  

You and I probably have, from our parents' exposure to chemicals, virus, or
normal cosmic rays, several random mutations in our genetic material, just
waiting to be passed on.  For any given union of sperm and egg there is a
50% chance that any one of these mutations will be passed on to our
children.  If the characteristic is recessive, and I have it and you don't,
it won't express in our children.  So long as the relative incidence of
occurrence of the gene is small, it does not represent a threat to the
population.  In in/line breeding you raise the relative incidence of
occurrence in a specific population (of good or bad genes), then outbreeding
spreads the characteristic throughout the general population.  You can say
that inbreeding intensifies and outbreeding extensifies the problems.  

Close breeding can be utilized only so long as there is extensive and
ruthless culling of the stock for any bad characteristic.  You cannot
continue to breed dogs that have genetic problems no matter how beautiful
the coat, or fine the confirmation.  You not only cannot breed them, but you
must look closely at the parents, and siblings, and half-siblings
particularly.  

Generally I would recommend outbreeding only.  No matter what the
characteristic you seek, you can generally find it in outside stock.  But
examine any potential breeding closely.  They may have their own problems,
but that is another rant . . I mean, story.  Open discussion of any genetic
problems may hurt now, but will help the breed in the long run.

Jackie Mowery
jlmowery@amaonline.com