DNA tests and Laboratories

[michaelundinaeichhorn]

Originally Posted by mijke

But maybe I am wrong! So please Ina, correct me when there are other reasons why they need more Csw’s for validation.

HD is for sure caused by several genes, that has to be so because there are more than one bone involved in the joint and there are different forms of causes of HD (to small Caput femoris, to low Norberg degree and so on). Though it is no longer discussed that HD is a genetic desease there are factors like too much training or too highly energetic food in the growth period that have a great influence on the severeness of the genetic caused desease.
So there is not only one reason or one gene mutation that has to be found but very likely the combination of genetic factors that is the reason, at least several different genes. That of course makes research much more difficult, takes much more time and dogs.
Anyway every genetic test that has been validated on one breed has to be checked on every new breed because there are defects with identical symptoms but caused by different mutations. But when you already have one working test you look in every new breed if the genes for the defect are the same or not. If you look for one mutated gene like in the dwarf test you only need one dog, if you look for different genes like in polygenic defect like HD you need more dogs because one dog with HD E may show a defect on the genes 1+3 and the other on 2+4 (just as an example, I am not that far in detailes about this test), or the combination of 1+4 causes severe HD, the combination of 1 + 2 doesn´t.
So as far as I understood they only need 24 dogs to check if they show the same mutations but about 200 to validate a working test.

[Juniorwolf]

Hello Ina and/or Mijke,

I am trying to follow this post, but sometimes it is a little too technical for me... something I would like to know(I think Mikael also asked this question earlier) is how excat will a HD DNA test be, I mean if they only have found the difference between HD A and HD D/E ? does this mean that, when the test is validated, it will only be possibe to say if the result is very good or very bad(not as excat as xray) ? ...or did I misunderstand ?

Thanks for keeping this very interesting topic public, so I(and others) can follow this

Greetings Rolf

[mijke]

Ina did have contact with the university.
So I think she can explain the best , what on this moment the (validated) DNA test for the GSH exactly can tell about the HD of a individual GSH.

[michaelundinaeichhorn]

I just asked them to make sure I didn´t get anything wrong.
In future it will be possible to make a selection of studs or dogs with this test and you can already start in puppyage. You can say which dogs are likely to get HD, which pairings are not sensible to make or which dog should be left out of breeding.
At this actual period you need both the x-rays and the blood to control the test (Yes I also think they can´t charge 300 Euros for that at the moment!!) and there is no result of breeding-selection at the moment in GSH, what means it will take several years till you will have statistics.
I still think this is a test of very high value for every breed but I also agree that there is no sense to pay for it as long as we have to pay for it on our own because the benefit at the moment for the breeder himself is low and our breed isn´t able to bring up this amount of money for a research projekt.

So in my opinion we should start with a blood bank, make a database for that dogs and wait for interesting research projects and the result of the test in the GSH.
DNA-tests will be the future and a good thing to avoid health problems in breeds so we should get ready for that.

[Juniorwolf]

Hi Ina,

Thanks for your answer

So this is how I understod it : for many years to come, xrays will still be necessary and sometime in a far away future, it will be possible to give only HD-results "good" or "bad" by DNA, but not more specific than that... and maybe in an even further away future it will be possible to give exact(A,B,C,D,E) HD-results from DNA ...for both GSD and CSW !

Please correct me if I am wrong ?

Greetings Rolf

[saschia]

Hi Rolf,

I don't think you'll ever be able to give HD A/B/C/D by DNA, as there is a lot of environmental influence on the definitive results. But you'll be able to say if the dog or it's offspring will be more or less succeptible to having dysplasia or not. You can never rule out damage made by irresponsible owners (like hard training of obese dog during it's development).

[michaelundinaeichhorn]

Originally Posted by saschia

Hi Rolf,

I don't think you'll ever be able to give HD A/B/C/D by DNA, as there is a lot of environmental influence on the definitive results. But you'll be able to say if the dog or it's offspring will be more or less succeptible to having dysplasia or not. You can never rule out damage made by irresponsible owners (like hard training of obese dog during it's development).

Exactly, the systhem of A,B etc. was created apart from telling how severe the problem of the specific dog is to say something about his breeding worth (I am sure that is not the right English word but hope it is understandable). If a dog is A,B or C doesn´t matter for the dog, even the C is not likely to cause problems in a family dog but it is important if you look a pairings. When you can judge about this by DNA there is no need for this classification any longer.

If you look at some A dogs you will find that an A and even As over several generations don´t grant for A offspring. A very good example are the brothers Good Boy and Grey Wolf z Molu es, they are even out of one litter but the HD-results of their offspring are two different worlds (and some of the bad resulst seem to have been removed) and nobody can tell me this all results in stupid puppy-owners ore classification sythems, it´s bad luck in genetics. If we would have a test we could say in advance how the results of a pairing are likely to be.