In my breed we have a reasonably new test for LPN1 and results are clear, carrier, affected.
The test is for a form that accounts for approx one third of the LPN cases so even clear dogs can get symptoms (other forms of LPN).
LPN1 affected dogs get symptoms at young age so are unlikely to be used for breeding.

The inheritance mode is simple,
clear+clear =clear pups,
carrier+clear = 50% clear/50% carrier pups
Carrier + carrier = 25%clear, 25% carrier, 50% affected pups etc
The top two combinations being recommended as so no affected pups are born (not all countries are testing yet and results are not yet published anywhere unless owners sends them on).

Current numbers from labs that developed the testing is that approx 15% of dogs are carriers, although looking at public lists, it is obvious people are not publishing the dogs with carrier status as freely as clear dogs, as the public lists make it look like carriers are pretty rare.

I am interested in what is the protocol in other breeds with illnesses with similar inheritance mode&genetic testing :) (possibly had the test for years opposed to our relatively new test) and where has the testing developed over the years?
Have people taken on the testing?
Are pups with clear+clear parentage getting a status "clear by parentage" or is the requirement to still test them to give them official clear status?
Are breeders being shy using dogs that have a carrier status?
When breeders are breeding from a carrier+clear are they getting whole litters tested before homing the pups?
Is there now less carriers due to breeders using the results to their benefit?

In my breed we've had DNA tests for a number of conditions for a few years now. All of the conditions tested for have a simple recessive mode of inheritance which means that there has to be one copy of the gene from each parent for the offspring to be affected by the condition( i.e. the progeny inherits 2 copies) one copy  from either of the parents for the offspring to be a carrier of the condition ( i.e. one copy inherited) and obviously, if neither parent has a copy of the gene, the offspring are clear of the condition by parentage.

What you need to understand, and I believe this was a common misconception ( no pun intended), is that when a carrier to normal ( clear) mating is done , each puppy has a 50% chance of inheriting carrier status and not the litter and so on. In theory , therefore, you could have carrier to carrier and all the litter normal but equally so, all affected . The only certainty is clear to clear and affected to affected. That is my understanding anyway. There may be modifying genes at play that could skew this.

The DNA tests are a useful tool for breeding Many in my breed use carrier to normal in an eye condition which can be very insignificant clinically. Another of the conditions can be lethal in affected puppies and I would not use a carrier dog . I understand that in some breeds the gene pool is very small and many of the dogs are carriers or affected by a condition. Breeders are using affected to normal and carrier to carrier with their eyes open because otherwise the genetic diversity within the breed would be lost and this would be to the detriment of the health of the breed.

Possible carrier puppies should be tested before they go to their new homes but as this is extremely expensive  it is often only done when the new owner is going to breed from the puppy. Most breeders put a clause in the sales contract obliging new owners to DNA test should they decide to breed.

In my breed we imported a fatal recessive disease with our new bloodlines.  My now 12 yr old male was an issue of one of these import animals he proved to be a carrier, I DO breed carrier x normal or normal x normal.  As we have no affected dogs in the UK we don't have to consider that one but as our gene pool is very small I personally would use an affected x normal mating if the affected dog was an amazing example of the breed.

I used to test all issue from my carrier x normal litters but decided against it after a couple litters due to everyone only wanting normal pups!  I now use the potential of producing a carrier or worse still an affected as a way of ensuring the pups aren't bred willy nilly, carrier status has no bearing on the dogs health so if you're wanting a pet or show with no breeding testing is not necessary.

I do however test any issue prior to looking at breeding even if they are from clear parents, there had been a problem a few yrs back with the test giving false normals.  It was found a problem had occured when a normal x normal litter were tested for export to Sweden where a normal certificate is needed regardless of parental status, 2 of 4 pups were found to be carrier.  This error has now been rectified but I will still test my normal x normal litters first generation to ensure they truely are normals.

I agree mostly with the above, not sure if we've the same breed, but I wouldn't worry as much about using a carrier for the eye complaint they get which isn't life threatening and doesn't deteriorate with age.  I would aim to breed the dogs I like until I got rid of this from my lines. There are two fatal diseases (1 death usually under 4 months and the other about 2/3 years) fortunately in the UK the latter is almost non existent (but is elsewhere in world) the first is uncommon and I'd wish to keep it that way. I wouldn't use a carrier for this disease because even if you sell to responsible people there is a chance further down the line that irresponsible people will breed, not test or sell to people who don't.  Due to 'ignorance' there has been a puppy die from this disease in the UK fairly recently after two carriers weren't tested although the original breeder was aware of their dog's status - ie sold a pup without telling the new owner it may be a carrier.  We have enough good dogs in the UK without - imo - using carriers of this disease.  It would be a very different thing if it was very common as they found in Australia when the first one of these was found and they didn't have a DNA test - the breeders got together to avoid the lines carrying this disease and that's when they found the second.  It was always there, of course, but few pups had died (put down to 'fading puppy' syndrome) as few carriers had come together.  Fortunately a DNA test for both was found and now there are no excuses for dogs to die.

Whoops, just reread my post. Carrier to normal would not produce affected. I meant to say 50% chance of normal/ 50% chance carrier. And so on !
Must stop posting without editing !

I personally find gene testing fasinating coat colour,health testing,lenghth and nose colour ect and i love doing 'the math'..i wont comment on my breed as im no expert although ive reserched gene testing for 18 months roughly now and think i have a pretty good picture on it..i wouldnt want to give falase information so ill wait for someone eles to comment....

interesting thread...

> What you need to understand, and I believe this was a common misconception ( no pun intended), is that when a carrier to normal ( clear) mating is done , each puppy has a 50% chance of inheriting carrier status and not the litter and so on. In theory , therefore, you could have carrier to carrier and all the litter normal but equally so, all affected . The only certainty is clear to clear and affected to affected. That is my understanding anyway. There may be modifying genes at play that could skew this.

Oh, yes. I do understand the inheritance and that the percentages are pot luck when it comes to amount of pups in the litter, I just was just explaining the mode as did not know the correct term people would understand. From your post :0 it is simple recessive mode of inheritance.

I just thought it would be interested to see what goes on with other breeds.
In my breed, first there were hysteria, many people were "dumping" the carriers as should not be bred from etc.
But it seems in a year or so people have actually studied a little more or dare I say had their own dogs tested and ended up with carriers themselves -That can change your attitude pretty quickly& make you want to study more before "throwing the baby out with the bath water" :)... and now carriers have been used, more so with girls at the moment, don't know many carrier males being used so far.

Same thing happened in my breed when  carriers of the often clinically insignificant eye problem were 'dumped' when the test was newly available.
The other two conditions we have DNA tests for are much more serious and can be lethal. Personally I wouldn't breed from carriers of those conditions. I also think that stud dogs should be clear/normal for all  hereditary conditions that we have DNA tests for because mathematically they can have the most influence on a breed.
Just my opinion. I know some will argue that it can be justified in 'exceptional' dogs.

so what causes a dogs nose to not be black my dog (as you will know ive mentioned it enough lol) is liver and white so aparantly carries the reccesive dilute gene but her nose is also liver coloured what causes it ? what good books are there for me to read up on genetics already invested in the newer version of the BOTB im not planning on breeding but i have the older version and loved it so have bought the new one , i do love reading up on complicated things to get the old brain working (and aching lol)

>my dog (as you will know ive mentioned it enough lol) is liver and white so aparantly carries the reccesive dilute gene but her nose is also liver coloured what causes it ?

No, liver isn't a dilute gene, but it is generally recessive, and will only be visible if the dog has no copy of the black gene (which masks the liver gene). So a liver dog can't have a black nose, because it doesn't have the gene for black.

ahhh i think i understand now :) wow this is fasinating

In border collies the black and brown/red are caused by the same gene - but acting differently, brown/red (called liver in other breeds) is recessive and yes the dog's noses will not be black because the black bit of the gene isn't acting in the dog, just the brown bit.  Sable and tri colouring are caused by the same gene - again one type of this gene will cause the overall sable colour and one type will cause the tri patterning on an otherwise black/brown dog.  In border collies the sable/tri gene is recessive - in shelties it's dominant, with black and white being recessive.  Shelties don't have the brown/red gene in general. 

In border collies dilution can be recessive - black dilutes to 'blue' and brown/red dilutes to 'lilac'.  Or the merle gene which is dominant also shows a dilution on the black/brown gene.  In general it doesn't show on white or sable/tri colourings.

http://www.vetgen.com/canine-coat-color.html

Take a read here ashsbt I collect samples many yrs ago for them when they were first investigating coat colours.  In the US and other countries only blacks of my breed can be exhibited with colour production frown upon so it was necessary and helpful to develope these tests.  Here in the UK we can exhibit any solid colour so had lots of animals to collect dna and coat samples from with most breeders more than happy to supply for research purposes.