PRA rcd4 RESULTS

[Gillian Kennedy-Sloane]

As an interim measure until the official register provided by the Kennel Club is fully up and running, the SEISC has decided to offer an opportunity for owners to post their recent PRA rcd4 DNA test results.
This will be on our PRA rcd4 page.
This is available to all owners worldwide not just SEISC members and will be in a similar format to that already used by the Kennel Club.

For further details please see the Club website www.seisc.co.uk.

 

Listing will be available sometime today - slight kink in my "html"  !!

[Margaret Sierakowski]

I think that is how it should be done, Carmel.

 

[Michelle Webster]

It is all worked on trust, just the same as buying a puppy. Unless you 'know' the dogs concerned, you take it on trust that the parents listed on your puppy's pedigree are as listed, there is no way to verify this, you just have to trust the breeder. As far as I can see, the only way to stop any possible cheating would be to make it compulsory to microchip every puppy and check these details every time they are tested for something, which would probably mean a visit to the vet and this of course will only increase the cost and then probably less dogs would be tested. Anyone who is corrupt enough to try to get round the system by sending in swabs from a different dog will probably get caught down the line when problems are produced.

[Ann Millington]

I agree, Wilko.  Having spent years  with CLAD & vWD testing in IRWS requiring blood samples, I can say that the use of swab samples encourages more testing. Blood samples meant an appointment with a vet, - some (many) vets conducted a full health check of the dog - and charged for it, then charged for taking the blood and charged for posting it to the AHT - overseas blood samples had to have an import charge too!  As we know from ELISA screening, blood samples can easily deteriorate if delayed in transport... The system with swab samples is that the kits are free, you can take the sample in the peace of home and just post them yourselves - this is definitely more user-friendly.

As for cheating - what is the point? Yes, the false information will be revealed in time - through 'contradictory' results in progeny and traced back to the shame of the cheat.  But I'm pretty sure  the rumour mill will have cast aspersions far and wide long before this!

Permanent ID is a really good thing, I guess it is almost automatic in most countries?

One thing we notice in our campaign to get IRWS over age 8 years DNA samples, is the requirement for tattooing or microchipping.  Some old dogs are not chipped or tattooed and their owners are reluctant to 'put them through it'.  

The thing that makes me cross is the soaring price of all the tests, I can't think how a test one day can cost a substantial amount more the next day - what is done differently that makes it cost more?

 

[Lena]

I am convinced they will approve tests from ATH if they are made from blood samples.

 

[Lena]

This is what I have been told is the policy of the Swedish kennel club - it has nothing to do with my own personal opinion. If you want to know the exact reasoning behind it you will have to contact them for an answer.

 

[Margaret Sierakowski]

There are two possible reasons for preferring a blood sample. Firstly the AHT themselves used to say a swab was less reliable than a blood sample because of the possibility of contamination, although now they accept swabs for DNA testing. Secondly, unless the swab is taken  by a vet , who checks the microchip at the same time, there is a no 100% guarantee the swab is from the named dog. And Wilko, I'm not throwing doubt or witch hunting, just pointing out that a system which uses unverified swabs leaves a loophole for abuse. I would be happier to see swabs taken and verified by vets from microchipped dogs

 

[Margaret Sierakowski]

Slightly cynically, the AHT appear to have abandoned their reservations about the reliability of swabs, possibly because of the growing volume of testing they now do for dogs from outside the UK. It was a problem testing on bloodsamples from outside the UK, the samples would deteriorate if they took several days to arrive, and didnt the sender have to get a license to import blood into the UK? Much easier to send swabs from overseas to the UK.

[eva ciechonska]

I know that if the AHT suspect a swab sample to be contaminated they send another kit for retesting so, since the CLAD business where the results from a batch of samples (done by blood test) were reversed, they have been scrupulously careful.

I am still bemused about this business of suspected cheating.  I cannot for the life of me understand why anyone would want to substitute one dog for another.  Surely re-submitting a swab or blood test of a clear dog under the name of another would be discovered by virtue of DNA profiling.  In any case where is the benefit of this to the breeder?  It is of no help to them if they want to eliminate a specific condition.  Maybe I am just being naive in this respect.

Perhaps to eliminate doubt swabs could be taken and verified by vets from microchipped dogs as Margaret suggests.

As to not accepting the reliability of swabs well blood samples can just as easily become contaminated.  Buccal swabs are taken to ascertain parentage and, as Silke says, in police investigations etc.

 

[Henriette van der Zwan]

Hi! The main reason for using blood and not swabs in genetic testing is that blood yields almost three times the amount of DNA than swabs. And you also get a lot of dirt with swabs, even if you rinse the dog's mouth.With humans it is another story as they (hopefully!) brush their teeth regularly and don't eat and lick anything they see! Some owners also brush the cheeks too lightly and then you get NO DNA from the swab. With blood you are guaranteed that it will work. Some labs use only blood, some only swabs. A new way is with the use of saliva, where you put a sponge in the dog's mouth to absorb the saliva. It works great and yields a high concentration of DNA, but the technology is still new and it is a bit expensive.

[Susan Stone]

Good to have a professional here! Thanks, Henriette.

[Dee Rance]

Apparently this test was designed for swabs, and blood makes it a little bit more difficult...that is why there is an extra charge for the bloods I think...

[Henriette van der Zwan]

Basically if you have swabs or blood or a piece of skin or meat or hair or anything it acts as a source of DNA. You then extract the DNA from this source (no matter what it is). The techniques to get the DNA from the source differ slightly (e.g. with blood you need to remove all the other stuff in blood you don't need and with swabs you remove the dirt) but at the end you wash the source until you get a clear DNA sample. It could be that AHT has an automated program that extract the DNA from the swabs and if you send in blood they have to use a different platform and that is why it costs more? After you have the DNA you only want to look at the PRA or Clad or whatever gene, you don't need ALL the DNA. So we do what is called a PCR reaction that cuts the gene out and amplify it millions of times. Then the gene is sequenced where the specific base sequence is determined. I'm not sure what the mutation for PRA-rcd4 is, but for PRA-rcd1 there is one change in the sequence from a G>A and Clad C>G. This alters the function of the gene and leads to the symptoms of the disorder.

The only reason I can think of why they charge more is that the blood extraction is not automated but the test will work the same no matter what source of DNA you get.

Hope it helps!