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WindfallMastiffs

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Reply with quote  #76 
Steve wrote:
Is it possible that a damaged piece from the Y chromosome is responsible in some cases? Perhaps, but until we get the genome up and running, with many comparatives to use as a guide, we can't be sure.

Until then, it's better to be over-cautious than under-cautious!

 
>>>ABSOLUTELY!!!
But I keep hearing it comes from mom, there is no guarantee to this, tho that is the theory, still not 100% certain.  I just don't like that when some people read these boards, they think they got it when in fact none of us have it, not even the researchers!
 
Anita wrote:
If the formation of stones is what makes the test positive (and by positive, I'm thinking that means the dog has cystinuria), then how can dogs without stones be positive?

 
>>>>A dog with stones is absolutely positive, but a dog without stones, can have the amino acid Cystine show up in the urine, which makes the dog positive.  A dog with the amino acid Cystine, is at risk of forming stones.  Like the precursor.  However not all cystinuria dogs form stone.  Why, that is a good question.
 
Jan

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steveoifer

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Reply with quote  #77 
Quote:
But I keep hearing it comes from mom, there is no guarantee to this


You can be assured that it comes from mom!

Otherwise, how would affected males pass it to females?

Males pass their X to females, that X comes from the female into the male.

The researchers are speculating that a fragment from the Y might be involved in passing from male to male, or linking up with an affected X in the male, which may cause stone formation to form in some rather than others. This is pure speculation, since the researchers were at a dead end without genome studies! The probability is that we are dealing with a couple, or several polygenic X based alleles, but not more than that!



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For the betterment of the breed

"Above all, a uniform type should be aimed at by breeders and uniformity of type can only exist in a proportionate ratio in the purity and distinctiveness in any breed"!.........M. Moore
"If breeds did not adhere to a specific shape, form, and colour range, or if breeders disregarded this blueprint, the breed would degenerate to the point that it would hardly resemble the breed at all. Selective breeding does not just create breeds- it preserves them as well." Breeding purebred dogs inherently means accepting limitations on your freedom to just breed anything...Catherine McMillan
" A reinforced consolidation of the American and British standards could be the basis for restoring our breed to the gladiatorial glory of its ancient past, in capability if not in usage".....Norman Howard Carp-Gordon
"I can live with doubt, or not knowing, rather than to have answers that might be wrong"...Richard Feynman
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Comstock

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Reply with quote  #78 
Hi Anita,

Cystinuria positive males are just that whether or not they form stones.  They have the disease and they can pass it on.  I would not use one in a breeding program.

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Caroline Tobin
Comstock Mastiffs
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Kiokeemastiffs

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Posts: 453
Reply with quote  #79 

  The test that we do depends on detecting the cystine in the urine--when stone are formed (from the cystine crystals)  it makes the test results show positive.  This is one of the reasons why a dog may not be positive until age 2, 3, or--he just has not had enough crystals to "make"" any stones yet.

Also--if the owner suspects the "possibility" of Cystinuria and places the dog on the "preventative" diet--a dog with cystinuri may never test positive.  IF you do not collect the urine at the correct time after feeding--you can alter the results.  IMO--there are just too many varabiles that can influence the test results.  Basically, it's only good as a screen tool that will detect only the more positive dogs.  We really need a DNA test in order to clear this trait from our dogs..

If only 1 in 6  "positive" males actually form stones--our current test could possible miss detecting a positive male.  This is the reson why I would be very leary of using in boy who has a C+ brother!  IF it's sex linked  (he will get 1 of the 2 Xs from his dam--one could be clear and one could be a carrier)--sure he has a 1 in 2 chances of being positive or being clear!

I think my plan would be to collect his semen and a blood sample and freeze him at 2-3 years of age.  I would contiune to test him yearly  and if by some good chance of fortune a DNA test is developed==have him tested.  If he turns out clear--then I could use the semen for breedings--if he is "positive"--I would dump it.

I may even want untill he is 5-6 years old--if he has remained clear and negative on his testing--I would use his semen.

As a breeder, we all hate to pass on using a good dog that we have produced, but we also do no need to chance continiuning to pass on this hidden trait in our dogs.


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Cathy (Catie) C. Arney
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panzerakc

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Reply with quote  #80 
Okay, another go-round at this -

So it's the presence of cystine that makes a dog positive for cystinuria, whether there are stones or not?

I keep reading that there is no way to test the girls for this.  Does that mean, that for whatever reason, the girls don't, or won't, have cystine in their urine?

Thanks.

Anita
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steveoifer

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Reply with quote  #81 
Apparently!

One reason why the genome project is so important!

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For the betterment of the breed

"Above all, a uniform type should be aimed at by breeders and uniformity of type can only exist in a proportionate ratio in the purity and distinctiveness in any breed"!.........M. Moore
"If breeds did not adhere to a specific shape, form, and colour range, or if breeders disregarded this blueprint, the breed would degenerate to the point that it would hardly resemble the breed at all. Selective breeding does not just create breeds- it preserves them as well." Breeding purebred dogs inherently means accepting limitations on your freedom to just breed anything...Catherine McMillan
" A reinforced consolidation of the American and British standards could be the basis for restoring our breed to the gladiatorial glory of its ancient past, in capability if not in usage".....Norman Howard Carp-Gordon
"I can live with doubt, or not knowing, rather than to have answers that might be wrong"...Richard Feynman
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