Re: [pyrnet] Recessives and carriers

[JGentzel@aol.com]

In a message dated 12/21/00 9:58:05 AM Pacific Standard Time, 
lmweisser@olywa.net writes:


> .  Generation 3 in this
> case was not 12.5/87.5, it was 100% but even thinking 50% might have
> helped.


No, that's not correct.  You did not read what I had written previously.  
Once a carrier or affected is identified the score goes back to the 50/50 for 
each dog.  Probability tells us there will always be a few, hopefully ever 
decreasing number, of dogs who remain carriers as we breed the probabilities 
in our favor.   With two carriers you do not have 100% affected puppies 
anyway.  Even your dog with the 98 plus percentage of possibly being clear 
could be in that 1 plus percentage.  Under your scenario you must presume 
that dog is a carrier and has a 50/50 change of producing carriers or with 
another carriers dwarfs.  

Even though the genetics are quite different, I look at it as something like 
hip dysplasia.   I think we all know it will always be there.  We are ever 
vigilent and eliminate affected animals from our breeding program, but we 
know it might reoccur again somewhere down the line.  I think most of us 
think we have have good sucess with this method and feel it has been 
sucessful.  To feel otherwise, why would be bother.  I realize we can know 
sometimes when a dog is dysplasic before breeding, but clear dogs do produce 
dysplasia, so basically what is the difference?  

What you have just set up requires for ethical breeders with any of these 
carriers in their background to disclose to their puppy buyers that their 
puppy has a 50/50 change of being a carrier and producing dwarfs.  I 
challenge you to give me the name of one dog offspring from American stock 
that goes back 20+ years that does not have one of the carriers back there.  
Do you know anyone who tells their puppy buyers that their puppy has a 50/50 
chance of being a dwarf carrier, when it is back that many generations?  

I believe you are setting up a basically very false premise based on 
supposition and presumption, when science would require probability 
calculation as the more valid avenue to approach this problem.  Under your 
scenario we, none of us, should be breeding anything.  Is that what you 
intend and feel is in the best interests of the breed?  Tell us, then who is 
left breeding?  I do not intend for these words to come across as personal in 
any respect.  They are intended as a question not directed to any personal 
nature but the points in the question.

Joe